Wireless communication system, base station apparatus, mobile station apparatus, and wireless communication method

ABSTRACT

A mobile station apparatus ( 1 ) determines an uplink carrier component to which a physical downlink control channel instructing to start random access procedure corresponds. Provided is a wireless communication system in which a base station apparatus ( 3 ) and a mobile station apparatus ( 1 ) communicate with each other using a plurality of component carriers, wherein the base station apparatus ( 3 ) includes a random access controller ( 1012 ) that preliminarily allocates random access resources corresponding to a specific downlink component carrier, by means of which the mobile station apparatus ( 1 ) can start a random access communication, and a transmission processor ( 111 ) that transmits control information instructing to start the random access procedure, and wherein the mobile station apparatus ( 1 ) includes a random access processor ( 2012 ) that, upon receipt of the control information instructing to start the random access procedure, starts the random access procedure by means of the random access resource corresponding to a specific downlink component carrier preliminarily allocated by the base station apparatus ( 3 ).

This application is a Divisional of co-pending application Ser. No.13/366,075 filed on Feb. 3, 2012, and for which priority is claimedunder 35 U.S.C. §120, application Ser. No. 13/366,075 is the nationalphase of PCT International Application No. PCT/JP2010/062953 filed onJul. 30, 2010 under 35 U.S.C. §371, which claims the benefit of priorityof JP2009-183031 filed Aug. 6, 2009. The entire contents of each of theabove-identified applications are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to a wireless communication system inwhich a base station apparatus communicates with a mobile stationapparatus using a plurality of uplink carrier components and downlinkcarrier components, and relates to a base station apparatus, a mobilestation apparatus, and a wireless communication method.

BACKGROUND ART

Conventionally, the evolution in the radio access system and radionetwork of cellular mobile communication (hereinafter, referred to as“Long Term Evolution” (LTE) or “Evolved Universal Terrestrial RadioAccess” (EUTRA)) and the radio access system and radio network(hereinafter, referred to as “Long Term Evolution-Advanced” (LTE-A) or“Advanced Evolved Universal Terrestrial Radio Access” (A-EUTRA)), whichrealize higher-speed data communication using a frequency band widerthan that of LTE, have been under study in the third GenerationPartnership Project (3GPP).

In LTE, orthogonal frequency division multiplexing (OFDM) system whichis multicarrier transmission is used as the communication system ofradio communication from a base station apparatus to a mobile stationapparatus (downlink). Moreover, as the communication system of the radiocommunication from a mobile station apparatus to a base stationapparatus (uplink), SC-FDMA (Single-Carrier Frequency Division MultipleAccess) system which is single carrier transmission is used.

In LTE, on a downlink, a synchronization channel (SCH), a physicalbroadcast channel (PBCH), a physical downlink control channel (PDCCH), aphysical downlink shared channel (PDSCH), a physical multicast channel(PMCH), a physical control format indicator channel (PCFICH), and aphysical HARQ indicator channel (Physical Hybrid automatic repeatrequest Indicator Channel; PHICH) are allocated. On an uplink, aphysical uplink shared channel (PUSCH), a physical uplink controlchannel (PUCCH), and a physical random access channel (PRACH) areallocated.

The purposes of using the physical random access channel are toestablish synchronization between a mobile station apparatus and a basestation apparatus on an uplink and to request for the allocation ofradio resources of the uplink. When the mobile station apparatus and thebase station apparatus are out of synchronization, when the mobilestation apparatus has data information to be transmitted to the basestation apparatus by means of a physical uplink shared channel, or whenthe base station apparatus notifies the mobile station apparatus bymeans of a physical downlink control channel so as to start randomaccess procedure, the mobile station apparatus activates random access.

There are two access methods for random access: contention based randomaccess and non-contention based random access. The contention basedrandom access is an access method which may cause collision betweenmobile station apparatuses, and is the typically performed randomaccess. The non-contention based random access is an access method whichdoes not cause collision between the mobile station apparatuses, and isthe random access which is performed at the initiative of a base stationapparatus in a special case, such as during handover, in order toestablish synchronization between the mobile station apparatus and thebase station apparatus.

In the random access, the mobile station apparatus transmits only apreamble in order to establish synchronization. The preamble includes asignature which is a signal pattern representing information. Here,several tens of types of signatures are prepared so as to be able torepresent several bits of information. At present, a mobile stationapparatus is assumed to transmit 6 bits of information using thepreamble, and 64 types of signatures are assumed to be prepared.

FIG. 16 is a view showing an example of the procedure of the contentionbased random access according to a conventional art. First, a mobilestation apparatus 1, based on the downlink channel quality or the like,determines a range of signatures to be selected, and randomly selects asignature from the selected range of signatures and transmits a preambleby means of a physical random access channel (Message 1 (M1)).

A base station apparatus 3, upon receipt of the preamble transmittedfrom the mobile station apparatus 1, calculates, from the preamble, adeviation in synchronization timing between the mobile station apparatus1 and the base station apparatus 3, and performs scheduling (allocationof radio resources of an uplink, and specifying of a transmission format(message size) and the like) for the mobile station apparatus 1 totransmit Message 3. Then, the base station apparatus 3 allocates atemporary C-RNTI (Cell-Radio Network Temporary Identifier) to the mobilestation apparatus 1, and arranges an RA-RNTI (Random Access-RadioNetwork Temporary Identifier) corresponding to a physical random accesschannel having received the preamble, into the physical downlink controlchannel, and transmits a random access response including deviationinformation of the synchronization timing, scheduling information, thetemporary C-RNTI, and the number (also referred to as a random ID or apreamble ID) of a signature of the received preamble, by a physicaldownlink shared channel which the radio resource allocation included inthe physical downlink control channel indicates (Message 2 (M2)).

After confirming that the physical downlink control channel includes theRA-RNTI, the mobile station apparatus 1 confirms the content of therandom access response arranged in the physical downlink shared channelwhich the radio resource allocation included in the physical downlinkcontrol channel indicates. Then, the mobile station apparatus 1 extractsthe response including the number of the signature of the preamble whichthe mobile station apparatus 1 transmitted, corrects the deviation insynchronization timing, and transmits Message 3 including information,such as a connection request, by means of the allocated radio resourceand transmission format of the physical uplink shared channel (Message 3(M3)).

The base station apparatus 3, upon receipt of the Message 3 from themobile station apparatus 1, transmits to the mobile station apparatus 1a contention resolution indicating that the mobile station apparatus 1has succeeded in random access, i.e., no collision of preambles hasoccurred between the mobile station apparatuses 1, or indicating thatthe mobile station apparatus 1, when a collision of preambles isoccurring between the mobile station apparatuses 1, has overcome thecollision of preambles (Message 4 (M4)).

If having succeeded in receiving the contention resolution, the mobilestation apparatus 1 determines that the random access is successful, andterminates the processing related to the random access. Note that, ifnot having detected the number of a signature of the transmittedpreamble within a random access response receiving period, or if nothaving detected the contention resolution within a contention resolutionreceiving period, the mobile station apparatus 1 starts again from thetransmission of the preamble.

FIG. 17 is a view showing an example of the procedure of thenon-contention based random access according to the conventional art.First, the base station apparatus 3 notifies the mobile stationapparatus 1 of the information indicating the number of a signature andthe radio resource of a physical random access channel, using a physicaldownlink control channel and the like. The mobile station apparatus 1transmits a preamble including a signature of the number notified fromthe base station apparatus 3, by means of the physical random accesschannel notified from the base station apparatus 3 (Message 1 (N1)).

The base station apparatus 3, upon receipt of the preamble including thesignature of the number notified to the mobile station apparatus 1,calculates from the preamble a deviation in synchronization timingbetween the mobile station apparatus 1 and the base station apparatus 3.Then, the base station apparatus 3 arranges, into the physical downlinkcontrol channel, an RA-RNTI corresponding to a physical random accesschannel having received the preamble, and transmits a random accessresponse including the deviation information of synchronization timingand the number of a signature of the received preamble to a physicaldownlink shared channel which the radio resource allocation included inthe physical downlink control channel indicates (Message 2 (N2)).

After confirming that the physical downlink control channel includes theRA-RNTI, the mobile station apparatus 1 confirms the content of therandom access response arranged in the physical downlink shared channelwhich the radio resource allocation included in the physical downlinkcontrol channel indicates. Then, if the content includes the number ofthe signature of the preamble which the mobile station apparatus 1transmitted, the mobile station apparatus 1 determines that the randomaccess is successful, and terminates the processing related to therandom access (see Non-Patent Document 1, Paragraph 5.1).

In LTE-A, there is a need for backward compatibility with LTE, in otherwords, there is a need to enable a base station apparatus of LTE-A tosimultaneously perform radio communication with mobile stationapparatuses of both LTE-A and LTE and also enable a mobile stationapparatus of LTE-A to perform radio communication with base stationapparatuses of both LTE-A and LTE. Therefore, it is under study thatLTE-A uses the same channel structure as LTE does.

For example, in LTE-A, a technique (also referred to as spectrumaggregation, carrier aggregation, frequency aggregation, or the like)has been proposed for using a plurality of frequency bands (hereinafter,referred to as carrier components (CC) or component carriers (CC)), eachhaving the same channel structure as that of LTE, as one frequency band(wide frequency band).

Specifically, in communications using the frequency aggregation, foreach downlink carrier component, a physical broadcast channel, aphysical downlink control channel, a physical downlink shared channel, aphysical multicast channel, a physical control format indicator channel,and a physical HARQ indicator channel are transmitted, and for eachphysical uplink carrier component, a physical uplink shared channel, aphysical uplink control channel, and a physical random access channelare allocated. That is, the frequency aggregation is a technique,wherein on an uplink and on a downlink, a base station apparatus and aplurality of mobile station apparatuses simultaneously transmit/receivea physical uplink control channel, a physical uplink shared channel, aphysical downlink control channel, a physical downlink shared channel,and the like together with a plurality of pieces of data information ora plurality of pieces of control information using a plurality ofcarrier components (see Non patent literature 2, Chapter 5).

CITATION LIST Non Patent Literature

-   NON PATENT LITERATURE 1: “3GPP TS36.321 v8.5.0 (2009-03)”, Mar. 17,    2009-   NON PATENT LITERATURE 2: “3GPP TR36.814 v1.0.2 (2009-03)”, May, 2009

DISCLOSURE OF THE INVENTION

However, in the conventional art, a base station apparatus and a mobilestation apparatus perform communications by means of one set of anuplink carrier component and a downlink carrier component, and thereforeif the base station apparatus allocates a plurality of uplink carriercomponents and downlink carrier components to the mobile stationapparatus, there is a problem that a physical downlink control channelinstructing to start random access procedure, the physical downlinkcontrol channel being transmitted by means of a downlink carriercomponent, cannot indicate that a radio resource (random accessresource) of a physical random access channel corresponding to whichdownlink carrier component instructs the start of random accessprocedure.

The present invention has been made in view of the above circumstancesand has an object to provide a wireless communication system, a basestation apparatus, a mobile station apparatus, and a wirelesscommunication method, wherein when the base station apparatus allocatesa plurality of uplink carrier components and downlink carrier componentsto the mobile station apparatus, the mobile station apparatus candetermine that a physical downlink control channel instructing to startrandom access procedure, the physical downlink control channel beingreceived by means of any one of the downlink carrier components,indicates that a radio resource (random access resource) of a physicalrandom access channel corresponding to which downlink carrier componentinstructs the start of random access procedure.

(1) In order to achieve the above-mentioned object, the presentinvention takes the following measures. That is, the wirelesscommunication system of the present invention is a wirelesscommunication system in which a base station apparatus and a mobilestation apparatus communicate with each other using a plurality ofcomponent carriers, wherein the base station apparatus comprises: arandom access controller which preliminarily allocates random accessresources corresponding to a specific downlink component carrier bymeans of which the mobile station apparatus can start a random accesscommunication; and a transmission processor which transmits controlinformation instructing to start random access procedure, and whereinthe mobile station apparatus comprises a random access processor which,upon receipt of the control information instructing to start randomaccess procedure, starts the random access procedure by means of therandom access resource corresponding to the specific downlink componentcarrier preliminarily allocated by the base station apparatus.

(2) In the wireless communication system of the present invention, thetransmission processor transmits the control information instructing tostart random access procedure by means of one arbitrary downlinkcomponent carrier from among a plurality of downlink component carriersset in the mobile station apparatus.

(3) The wireless communication system of the present invention is awireless communication system in which a base station apparatus and amobile station apparatus communicate with each other using a pluralityof component carriers, wherein the base station apparatus comprises: arandom access controller which selects, from among random accessresources corresponding to respective downlink component carriers set inthe mobile station apparatus, a random access resource causing themobile station apparatus to start a random access communication; and atransmission processor which transmits control information instructingto start random access procedure by means of a downlink componentcarrier corresponding to the selected random access resource, andwherein the mobile station apparatus comprises a random access processorwhich, upon receipt of the control information instructing to startrandom access procedure by means of any of the downlink componentcarriers, starts random access procedure by means of a random accessresource corresponding to the downlink component carrier, by means ofwhich the control information has been received.

(4) In the wireless communication system of the present invention, thebase station apparatus and the mobile station apparatus communicatemessages for random access with each other by means of an uplinkcomponent carrier including a random access resource, by means of whichthe mobile station apparatus has started the random access procedure,and a downlink component carrier corresponding to the uplink componentcarrier.

(5) In the wireless communication system of the present invention, thetransmission processor transmits a radio resource control signalincluding information indicative of a random access resourcecorresponding to a specific downlink component carrier allocated to themobile station apparatus.

(6) In the wireless communication system of the present invention, thecontrol information instructing to start random access procedure furtherincludes, from among the random access resources corresponding to thedownlink component carrier, information indicative of a random accessresource, by means of which the mobile station apparatus can startrandom access procedure, and information indicative of a signature.

(7) In the wireless communication system of the present invention, therandom access controller, when instructing contention based randomaccess as a random access method to the mobile station apparatus, setsthe information indicative of a signature to a specific code point, andthe random access processor, when the information indicative of asignature is the specific code point, selects contention based randomaccess as the random access method.

(8) In the wireless communication system of the present invention, therandom access processor, when having selected the contention basedrandom access as the random access method, selects a random accessresource for starting random access procedure from among random accessresources corresponding to a specific downlink component carrierpreliminarily allocated by the base station apparatus.

(9) In the wireless communication system of the present invention, therandom access processor, when having selected the contention basedrandom access as the random access method, selects a random accessresource for starting random access procedure from among all the randomaccess resources corresponding to the respective downlink componentcarriers set by the base station apparatus.

(10) The base station apparatus of the present invention is a basestation apparatus which communicates with a mobile station apparatususing a plurality of component carriers, comprising: a random accesscontroller that preliminarily allocates random access resourcescorresponding to a specific downlink component carrier by means of whichthe mobile station apparatus can start a random access communication;and a transmission processor that transmits control informationinstructing to start random access procedure.

(11) The base station apparatus of the present invention is a basestation apparatus which communicates with a mobile station apparatususing a plurality of component carriers, comprising: a random accesscontroller that selects, from among random access resourcescorresponding to respective downlink component carriers set in themobile station apparatus, a random access resource causing the mobilestation apparatus to start a random access communication; and atransmission processor that transmits control information instructing tostart random access procedure by means of a downlink component carriercorresponding to the selected random access resource.

(12) The mobile station apparatus of the present invention is a mobilestation apparatus which communicates with a base station apparatus usinga plurality of component carriers, comprising a random access processorthat, upon receipt of the control information instructing to start therandom access procedure, starts random access procedure by means of arandom access resource corresponding to a specific downlink componentcarrier preliminarily allocated by the base station apparatus.

(13) The mobile station apparatus of the present invention is a mobilestation apparatus which communicates with a base station apparatus usinga plurality of component carriers, comprising a random access processorthat, upon receipt of the control information instructing to start therandom access procedure by means of any of downlink component carriers,starts random access procedure by means of a random access resourcecorresponding to the downlink component carrier, by means of which thecontrol information has been received.

(14) The wireless communication method of the present invention is awireless communication method which is used in a base station apparatuscommunicating with a mobile station apparatus using a plurality ofcomponent carriers, the method comprising the steps of: preliminarilyallocating random access resources corresponding to a specific downlinkcomponent carrier, by means of which the mobile station apparatus canstart a random access communication; and transmitting controlinformation instructing to start random access procedure.

(15) The wireless communication method of the present invention is awireless communication method which is used in a base station apparatuscommunicating with a mobile station apparatus using a plurality ofcomponent carriers, the method comprising the steps of: selecting, fromamong random access resources corresponding to respective downlinkcomponent carriers set in the mobile station apparatus, a random accessresource causing the mobile station apparatus to start a random accesscommunication; and transmitting control information instructing to startrandom access procedure by means of a downlink component carriercorresponding to the selected random access resource.

(16) The wireless communication method of the present invention is awireless communication method which is used in a mobile stationapparatus communicating with a base station apparatus using a pluralityof component carriers, the method comprising the step of: starting, uponreceipt of the control information instructing to start random accessprocedure, the random access procedure by means of a random accessresource corresponding to a specific downlink component carrierpreliminarily allocated by the base station apparatus.

(17) The wireless communication method of the present invention is awireless communication method which is used in a mobile stationapparatus communicating with a base station apparatus using a pluralityof component carriers, the method comprising the step of starting, uponreceipt of the control information instructing to start random accessprocedure by means of any of downlink component carriers, the randomaccess procedure by means of a random access resource corresponding tothe downlink component carrier, by means of which the controlinformation has been received.

According to the present invention, to a mobile station apparatus isallocated with a plurality of uplink carrier components and downlinkcarrier components by a base station apparatus, and can determine that aphysical downlink control channel instructing to start random accessprocedure, the physical downlink control channel being received by meansof any one of the downlink carrier components among the allocateddownlink carrier components, indicates that a radio resource (randomaccess resource) of a physical random access channel corresponding towhich downlink carrier component instructs the start of random accessprocedure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual view of a wireless communication system accordingto a first embodiment of the present invention.

FIG. 2 is a view showing an example of frequency aggregation processingaccording to the embodiment.

FIG. 3 is a schematic diagram showing an example of the configuration ofa downlink radio frame according to the embodiment.

FIG. 4 is a schematic diagram showing an example of the configuration ofan uplink radio frame according to the embodiment.

FIG. 5 is a schematic diagram showing an example of the configuration ofa signature according to the embodiment.

FIG. 6 is a schematic block diagram showing the configuration of a basestation apparatus 3 according to the embodiment.

FIG. 7 is a schematic block diagram showing the configuration of amobile station apparatus 1 according to the embodiment.

FIG. 8 is a conceptual view showing a relationship between a physicaldownlink control channel and a physical random access channel accordingto the embodiment.

FIG. 9 is a flow diagram showing an example of the operation of the basestation apparatus 3 according to the embodiment.

FIG. 10 is a flow diagram showing an example of the operation of themobile station apparatus 1 according to the embodiment.

FIG. 11 is a schematic block diagram showing the configuration of a basestation apparatus 7 according to a second embodiment of the presentinvention.

FIG. 12 is a schematic block diagram showing the configuration of amobile station apparatus 5 according to the second embodiment of thepresent invention.

FIG. 13 is a conceptual view showing a relationship between a physicaldownlink control channel and a physical random access channel accordingto the embodiment.

FIG. 14 is a flow diagram showing an example of the operation of thebase station apparatus 7 according to the embodiment.

FIG. 15 is a flow diagram showing an example of the operation of themobile station apparatus 5 according to the embodiment.

FIG. 16 is a view showing an example of the procedure of contentionbased random access according to a conventional art.

FIG. 17 is a view showing an example of the procedure of non-contentionbased random access according to the conventional art.

BEST MODES FOR CARRYING OUT THE INVENTION First Embodiment

Hereinafter, a first embodiment of the present invention will bedescribed with reference to the accompanying drawings.

FIG. 1 is a conceptual view of a wireless communication system accordingto the first embodiment of the present invention. In FIG. 1, a wirelesscommunication system comprises mobile station apparatuses 1A-1C and abase station apparatus 3. The mobile station apparatuses 1A-1C and thebase station apparatus 3 perform communications using frequencyaggregation to be described later.

FIG. 1 shows that in the radio communication from the base stationapparatus 3 to the mobile station apparatus 1A-1C (downlink), asynchronization channel (SCH), a downlink pilot channel (or referred toas also a “downlink reference signal (DL RS)”), a physical broadcastchannel (PBCH), a physical downlink control channel (PDCCH), a physicaldownlink shared channel (PDSCH), a physical multicast channel (PMCH), aphysical control format indicator channel (PCFICH), and a physical HARQindicator channel (physical hybrid ARQ indicator channel; PHICH) areallocated.

Moreover, FIG. 1 shows that in the radio communication from the mobilestation apparatuses 1A-1C to the base station apparatus 3 (uplink), anuplink pilot channel (or referred to as also an “uplink reference signal(UL RS)”), a physical uplink control channel (PUCCH), a physical uplinkshared channel (PUSCH), and a physical random access channel (PRACH) areallocated.

FIG. 2 is a view showing an example of the frequency aggregationprocessing according to the embodiment. In FIG. 2, the horizontal axisrepresents a frequency domain and the vertical axis represents a timedomain. As shown in FIG. 2, a downlink subframe D1 comprises a subframeof three carrier components (DCC-1; downlink component carrier-1, DCC-2,DCC-3) each having a bandwidth of 20 MHz. In each subframe of thisdownlink carrier component, a region hatched by lattice lines where thephysical downlink control channel is arranged and a non-hatched regionwhere the physical downlink shared channel is arranged aretime-multiplexed.

On the other hand, an uplink subframe U1 comprises three carriercomponents (UCC-1; uplink component carrier-1, UCC-2, UCC-3) each havinga bandwidth of 20 MHz. In each subframe of this uplink carriercomponent, a region hatched by diagonal lattice lines where the physicaluplink control channel is arranged, a region hatched by diagonally leftlines where the physical uplink shared channel is arranged, and a regionfilled with black color where the physical random access channel isarranged, are frequency-multiplexed.

For example, the base station apparatus 3, in a certain downlinksubframe, arranges a signal into the physical downlink shared channel ofone or more downlink carrier components among three downlink carriercomponents and transmits the same to the mobile station apparatus 1.Moreover, the mobile station apparatus 1, in a certain uplink subframe,arranges a signal into a physical uplink shared channel of one or moreuplink carrier components among three uplink carrier components andtransmits the same to the base station apparatus 3. Moreover, the mobilestation apparatus 1, in a certain uplink subframe, arranges a preambleinto a physical random access channel (random access resource) of oneuplink carrier component among three uplink carrier components andtransmits the same to the base station apparatus 3.

The uplink carrier component and the downlink carrier component, bymeans of which the mobile station apparatus 1 and the base stationapparatus 3 transmit/receive some of or all of random access messages,are paired. The base station 3 broadcasts by means of the respectivedownlink carrier components information related to random accesstransmission, such as information indicative of an uplink carriercomponent paired with a downlink carrier component, informationindicative of the configuration of a physical random access channel,which the downlink carrier component corresponds to, and thetransmission conditions of random access to notify the mobile stationapparatus 1.

For example, in FIG. 2, when DCC-1 and UCC-1, DCC-2 and UCC-2, and DCC-3and UCC-3 each serve as a pair transmitting/receiving a random accessmessage, the base station apparatus 3 broadcasts information indicativeof an uplink carrier component (UCC-1, UCC-2, UCC-3) paired with adownlink carrier component and information related to the random accesstransmission in a physical random access channel, which the downlinkcarrier component corresponds to, by means of the respective downlinkcarrier components (DCC-1, DCC-2, DCC-3). When the mobile stationapparatus 1 transmits Message 1 (preamble) by means of the physicalrandom access channel of UCC-1, the base station apparatus 3 and themobile station apparatus 1 performs transmission/reception of Message 2(random access response) by means of DCC-1. Note that the informationrelated to random access transmission of a plurality of downlink carriercomponents may be transmitted by means of one downlink carrier componentor respective downlink carrier components.

FIG. 3 is a schematic diagram showing an example of the configuration ofthe downlink radio frame according to the embodiment. FIG. 3 shows theconfiguration of a radio frame in a certain downlink carrier component.In FIG. 3, the horizontal axis represents the time domain and thevertical axis represents the frequency domain. As shown in FIG. 3, theradio frame of the downlink carrier component comprises a plurality ofdownlink physical resource block (Physical Resource Block; PRB) pairs(e.g., region surrounded by a broken line of FIG. 3). This downlinkphysical resource block pair is the unit of allocation or the like ofradio resources, and comprises a predetermined frequency band (PRBbandwidth; 180 kHz) and a predetermined time width (two slots=onesubframe; 1 ms).

One downlink physical resource block pair comprises two downlinkphysical resource blocks (PRB bandwidth×slot) continuous in the timedomain. One downlink physical resource block (the unit surrounded by athick line in FIG. 3) comprises 12 subcarriers (15 kHz) in the frequencydomain, and comprises seven OFDM symbols (71 μs) in the time domain.

In the time domain, there are a slot (0.5 ms) comprising seven OFDMsymbols (71 μs), a subframe (1 ms) comprising two slots, and a radioframe (10 ms) comprising ten subframes. In the frequency domain, aplurality of downlink physical resource blocks is arranged in accordancewith the bandwidth of a downlink carrier component. Note that a unitcomprising one subcarrier (15 kHz) and one OFDM symbol (71 μs) isreferred to as a downlink resource element (RE).

Hereinafter, the channels allocated within a downlink radio frame aredescribed. For each subframe on a downlink, a physical downlink controlchannel, a physical downlink shared channel, and a downlink referencesignal are allocated, for example. The physical downlink control channelis arranged from the first OFDM symbol of a subframe, and the physicaldownlink shared channel is arranged in the remaining OFDM symbols of thesubframe. With regard to the downlink pilot channel, the illustrationthereof is omitted in FIG. 3 for simplicity of description, but thedownlink pilot channels are dispersed and arranged in the frequencydomain and the time domain.

First, signals arranged in the physical downlink control channel aredescribed. In the physical downlink control channel, signals of downlinkcontrol information (DCI), such as a downlink grant (or referred to asalso a “downlink assignment”) and an uplink grant, which is theinformation used in controlling communications, are arranged. Note thatthe downlink control information has a plurality of formats.

Note that, the downlink grant comprises information indicative of themodulation scheme for a physical downlink shared channel, informationindicative of a coding scheme, information indicative of the allocationof radio resources, information related to HARQ (Hybrid Automatic RepeatRequest), and the like. Moreover, the uplink grant comprises informationindicative of the modulation scheme for a physical uplink sharedchannel, information indicative of a coding scheme, informationindicative of the allocation of radio resources, information related toHARQ, and the like.

Note that, HARQ is, for example, a technique, wherein when the mobilestation apparatus 1 (or the base station apparatus 3) transmits to thebase station apparatus 3 (or the mobile station apparatus 1) the successor failure (ACK (ACKnowledgement)/NACK (Negative-ACKnowledgement)) indecoding data information and if the mobile station apparatus 1 (or thebase station apparatus 3) cannot decode the data information due to anerror (NACK), then the base station apparatus 3 (or the mobile stationapparatus 1) retransmits the signal and the mobile station apparatus 1(or the base station apparatus 3) performs decoding processing on acomposite signal of the signal which the mobile station apparatus 1 (orthe base station apparatus 3) received again and the already receivedsignal.

To the downlink control information, a sequence obtained byexclusive-ORing a cyclic redundancy check (CRC) code (error detectioncode), which is generated from a bit sequence of downlink controlinformation, and an identifier is added. The mobile station apparatus 1can obtain the cyclic redundancy check code by further exclusive-ORingthis sequence using the same identifier. That is, the mobile stationapparatus 1 can determine from the identifier included in the physicaldownlink control channel whether or not the physical downlink controlchannel is the one transmitted to the mobile station apparatus 1.

For example, when a C-RNTI (Cell-Radio Network Temporary Identifier),which the base station apparatus 3 allocated to the mobile stationapparatus 1, is included in the physical downlink control channel, themobile station apparatus 1 determines that the physical downlink controlchannel is indicating the allocation of radio resources of the physicaldownlink shared channel addressed to the mobile station apparatus 1.

When the base station apparatus 3 instructs the mobile station apparatus1 to start random access procedure, the base station apparatus 3transmits the physical downlink control channel including downlinkcontrol information of a specific format, in which a specific region isset to a predetermined code point (e.g., a flag indicative of the typeof the format is “1”, and a flag indicative of the radio resourceallocation method is “0”, and all the pieces of information indicativeof the allocation of radio resources are “1”), and the C-RNTI allocatedto the mobile station apparatus 1 instructed to start random accessprocedure. Regions other than this specific region of the physicaldownlink control channel instructing to start random access procedureincludes the information indicative of the number of a signature andinformation indicative of the radio resource of a physical random accesschannel, into which the mobile station apparatus 1 may arrange thepreamble, among the radio resources of a physical random access channelwhich a downlink carrier component corresponds to.

The base station apparatus 3 sets to each mobile station apparatus 1 thephysical random access channel corresponding to a specific downlinkcarrier component, by means of which the random access procedure can bestarted, and notifies this set information to the mobile stationapparatus 1 by means of a radio resource control signal or the like.Note that the base station apparatus 3 may set the relevant informationcommon among all the mobile station apparatuses and broadcast thisinformation.

Next, signals arranged in the physical downlink shared channel aredescribed. The signal of data information (transport block) is arrangedin the physical downlink shared channel. In the embodiment, a downlinkgrant and a physical downlink shared channel whose allocation of radioresources is indicated by the downlink grant are arranged in the samesubframe.

FIG. 4 is a schematic diagram showing an example of the configuration ofthe uplink radio frame according to the embodiment. FIG. 4 shows theconfiguration of the radio frame in a certain uplink carrier component.In FIG. 4, the horizontal axis represents the time domain and thevertical axis represents the frequency domain. As shown in FIG. 4, theradio frame of the uplink carrier component comprises a plurality ofuplink physical resource block pairs (e.g., region surrounded by adotted line of FIG. 4). This uplink physical resource block pair is theunit of allocation or the like of radio resources, and comprises apredetermined frequency band (PRB bandwidth; 180 kHz) and apredetermined time width (two slots=one subframe; 1 ms).

One uplink physical resource block pair comprises two uplink physicalresource blocks (PRB bandwidth×slot) continuous in time domain. Oneuplink physical resource block (the unit surrounded by a thick line inFIG. 4) comprises 12 subcarriers (15 kHz) in the frequency domain, andcomprises seven SC-FDMA symbols (71 μs) in the time domain.

In the time domain, there are a slot (0.5 ms) comprising seven SC-FDMAsymbols (71 μs), a subframe (1 ms) comprising two slots, and a radioframe (10 ms) comprising ten subframes. In the frequency domain, aplurality of uplink physical resource blocks is arranged in accordancewith the bandwidth of an uplink carrier component. Note that a unitcomprising one subcarrier (15 kHz) and one SC-FDMA symbol (71 μs) isreferred to as an uplink resource element.

Hereinafter, the channels allocated within an uplink radio frame aredescribed. For each subframe on an uplink, a physical uplink controlchannel, a physical uplink shared channel, a physical random accesschannel, and an uplink reference signal are allocated, for example.First, signals arranged in the physical random access channel aredescribed. The physical random access channel (not shown) is arranged ina radio resource comprising a bandwidth of 72 uplink resource elements(six physical resource blocks) in the frequency domain and any of onesubframe to three subframes in the time domain.

Moreover, a subcarrier interval of the physical random access channel is1.25 kHz or 7.5 kHz and differs from the subcarrier interval (15 kHz) ofthe physical uplink control channel or the physical uplink sharedchannel. A plurality of radio resources of a physical random accesschannel are allocated in the radio frame (10 ms). The specificconfiguration of the radio resource of the physical random accesschannel is notified to the mobile station apparatus 1 as broadcastinformation.

In the physical random access channel, a preamble is arranged in orderfor the mobile station apparatus 1 and the base station apparatus 3 tosynchronize with each other. The preamble includes a signature which isa signal pattern representing information, wherein several tens of typesof signatures are prepared and several bits of information can beexpressed.

FIG. 5 is a schematic diagram showing an example of the configuration ofthe signature according to the embodiment. In FIG. 5, the vertical axisrepresent the number of the signature, the signatures from Signature 1to Signature 48 are used for contention based random access, while thesignatures from Signature 49 to Signature 64 are used for non-contentionbased random access.

The respective mobile station apparatuses 1 performing contention basedrandom access as the random access method randomly select a signaturesamong Signature 1 to Signature 24 when the transmission size of Message3 is small, while when the transmission size of Message 3 is large, therespective mobile station apparatuses 1 randomly select a signature fromSignature 25 to Signature 48. The signature when the message size issmall is typically selected when the channel performance is poor (or thedistance between the mobile station apparatus 1 and the base stationapparatus 3 is far), while the signature when the message size is largeis selected when the channel performance is good (or the distancebetween the mobile station apparatus 1 and the base station apparatus 3is close).

The mobile station apparatus 1 performing non-contention based randomaccess as the random access method is notified of any one signature,which the base station apparatus 3 has selected among the signaturesfrom Signature 49 to Signature 64, by means of the physical downlinkcontrol channel and the like. Note that, when the information indicativeof the number of a signature of the physical downlink control channelinstructing to start random access procedure is a specific code point(e.g., all are set to “0”), the mobile station apparatus 1 performscontention based random access. The base station apparatus 3 transmitsto the mobile station apparatus 1 the physical downlink control channelinstructing to start random access procedure, but for example when thereis no signature for non-contention based random access which can beallocated to the mobile station apparatus 1, the base station apparatus3 notifies the mobile station apparatus 1 so as to start contentionbased random access, by means of the physical downlink control channelinstructing to start random access procedure.

Next, signals arranged in the physical uplink control channel aredescribed. A physical uplink control channel is allocated to an uplinkphysical resource block pair (the region hatched by diagonally leftlines) at both ends of the bandwidth of the uplink carrier component. Inthe physical uplink control channel, there are arranged the signals ofuplink control information (UCI), which are information used incontrolling communications, such as channel quality informationindicative of the downlink channel quality, a scheduling request (SR)indicative of a request for allocation of radio resources of an uplink,and ACK/NACK with respect to the physical downlink shared channel.

Next, signals arranged in the physical uplink shared channel aredescribed. The physical uplink shared channel is allocated to an uplinkphysical resource block pair (non-hatched region) except for thephysical uplink control channel and the physical random access channel.In the physical uplink shared channel, there is arranged the signal ofdata information (transport block) which is the information except forthe uplink control information. In the embodiment, a physical uplinkshared channel, whose allocation of radio resources is indicated by anuplink grant, is arranged in an uplink carrier component within asubframe in a predetermined period after receiving the uplink grant.

Next, the uplink reference signal is described. A demodulation referencesignal (not shown) is arranged so as to be time-multiplexed with theradio resources of the physical uplink shared channel and physicaluplink control channel. A sounding reference signal (not shown) is, inthe time domain, arranged in the last SC-FDMA symbol in a subframe of aperiod which the base station apparatus 3 sets for each mobile stationapparatus, while in the frequency domain, it is arranged in thefrequency domain which the base station apparatus 3 set for each mobilestation apparatus.

FIG. 6 is a schematic block diagram showing the configuration of thebase station apparatus 3 according to the embodiment. As shown in theview, the base station apparatus 3 comprises an higher layer processor101, a preamble detector 103, a synchronization timing measurement unit105, a controller 107, a reception processor 109, a plurality ofreceiving antennas, a transmission processor 111, and a plurality oftransmission antennas. Moreover, the higher layer processor 101comprises a radio resource controller 1011 and a random accesscontroller 1012. Note that, in FIG. 6, the receiving antennas and thetransmission antennas are separately arranged, but the antennas may beshared using a thyristor or the like capable of switching theinput/output of a signal.

The higher layer processor 101 outputs the data information for eachdownlink carrier component to the transmission processor 111. Moreover,the higher layer processor 101 performs processing for a packet dataconvergence protocol (PDCP) layer, a radio link control (RLC) layer, anda radio resource control (RRC) layer. The radio resource controller 1011of the higher layer processor 101 performs the management and the likeof various kinds of configuration data, communication conditions, andbuffer conditions of the respective mobile station apparatuses 1. Therandom access controller 1012 of the higher layer processor 101 performsthe control related to random access of the respective mobile stationapparatuses 1.

In the above-described processing, the radio resource controller 1011 ofthe higher layer processor 101 allocates a plurality of uplink carriercomponents and downlink carrier components to the mobile stationapparatus 1 in accordance with the number of downlink carrier componentsand uplink carrier components which the base station apparatus 3 can usefor radio communication, the number of downlink carrier components anduplink carrier components which the mobile station apparatus 1 cansimultaneously transmit or receive, and the like.

The radio resource controller 1011 generates the information arranged ineach channel of each downlink carrier component or obtains the same froman higher node, and outputs the same to the transmission processor 111for each downlink carrier component. For example, the radio resourcecontroller 1011 generates downlink control information and a randomaccess response which is one type of data information, and outputs thesame to the transmission processor 111.

The radio resource controller 1011 allocates, among the radio resourcesof the uplink carrier component allocated to the mobile stationapparatus 1, a radio resource, into which the mobile station apparatus 1arranges a physical uplink shared channel (data information), to themobile station apparatus 1. Moreover, the radio resource controller 1011allocates, among the radio resources of the downlink carrier componentallocated to the mobile station apparatus 1, a radio resource into whicha physical downlink shared channel (data information) with respect tothe mobile station apparatus 1 is arranged. The radio resourcecontroller 1011 generates the downlink grant and uplink grant indicativeof the relevant allocation of radio resources, and transmits the same tothe mobile station apparatus 1 via the transmission processor 111.Moreover, the radio resource controller 1011 includes the C-RNTIallocated to the mobile station apparatus 1, which the downlink grant oruplink grant corresponds to, into the relevant downlink grant and uplinkgrant.

The radio resource controller 1011, based on the control informationfrom the random access controller 1012, generates the physical downlinkcontrol channel instructing to start random access procedure. The radioresource controller 1011, based on the channel quality of a downlinkcarrier component allocated to the mobile station apparatus 1instructing to start random access procedure, the overhead of a physicaldownlink control channel, and the like, selects one arbitrary downlinkcarrier component, and transmits a physical downlink control channelinstructing to start random access procedure, to the mobile stationapparatus 1 via the transmission processor 111 by means of the selecteddownlink carrier component. Moreover, the radio resource controller 1011includes information indicative of the radio resource of the physicalrandom access channel corresponding to the downlink carrier componentallocated to the mobile station apparatus 1 which the relevant physicaldownlink control channel corresponds to, the information indicative ofthe number of a signature, and the C-RNTI, into the physical downlinkcontrol channel instructing to start random access procedure.

The radio resource controller 1011 selects one downlink carriercomponent based on the control information from the random accesscontroller 1012, and allocates, among the radio resources within theselected downlink carrier component, a radio resource in which a randomaccess response is arranged. Moreover, the radio resource controller1011 includes the RA-RNTI, which is input from the random accesscontroller 1012, into the downlink grant indicative of the relevantallocation of radio resources.

The radio resource controller 1011 selects one uplink carrier componentbased on the control information from the random access controller 1012,and allocates, among the radio resources within the selected uplinkcarrier component, a radio resource in which Message 3 is arranged.Moreover, the radio resource controller 1011 generates the uplink grantindicative of the relevant allocation of radio resources, includes thesame into the random access response, and transmits the same to themobile station apparatus 1 via the transmission processor 111. Note thatthe uplink grant included in the random access response includes neithera cyclic redundancy check code nor a mobile station apparatusidentifier. The random access response includes a deviation amount ofthe synchronization timing for each of a plurality of signatures inputfrom the random access controller 1012, a temporary C-RNTI, and theuplink grant which the radio resource controller 1011 generated.

Based on the uplink control information (ACK/NACK, channel qualityinformation, scheduling request) notified by means of the physicaluplink control channel from the mobile station apparatus 1, theconditions of a buffer of the mobile station apparatus 1, and variouskinds of configuration data of the respective mobile station apparatuses1 which the radio resource controller 1011 set, the radio resourcecontroller 101 generates control information in order to control thereception processor 109 and the transmission processor 111, and outputsthe same to the controller 107.

In the above-described processing, the random access controller 1012 ofthe higher layer processor 101 generates: broadcast informationincluding the information related to random access, such as theinformation indicative of a pair of an uplink carrier component and adownlink carrier component for transmitting/receiving some of or all ofthe messages, configuration (allocation of radio resources and the likeof a physical random access channel) of a physical random access channelwithin the uplink carrier component, and the transmission conditions(random access load) of the random access; a random access response;contention resolution; and the like, and outputs these controlinformation to the radio resource controller 1011 so as to transmit thesame to the mobile station apparatus 1 via the transmission processor111.

The random access controller 1012 sets physical random access channelscorresponding to a specific downlink carrier component, by means ofwhich random access procedure can be started, to the respective mobilestation apparatuses 1 based on the transmission conditions of the randomaccess, the channel quality of an uplink carrier component, and thelike, generates information indicative of the set specific downlinkcarrier component, and includes this information into a radio resourcecontrol signal and the like, and outputs the resulting controlinformation to the radio resource controller 1011 so as to transmit thesame to the respective mobile station apparatuses 1 via the transmissionprocessor 111.

For example, when the base station apparatus 3 and the mobile stationapparatus 1 are out of synchronization while there is data informationto be transmitted in the mobile station apparatus 1, the random accesscontroller 1012 determines to instruct the mobile station apparatus 1 tostart random access procedure. The random access controller 1012allocates the radio resource and signature of a physical random accesschannel corresponding to a specific downlink carrier component set inthe mobile station apparatus 1. The random access controller 1012generates the physical downlink control channel for instructing themobile station apparatus 1 to start random access procedure, and outputsthe same to the radio resource controller 1011 so as to output the sameto the transmission processor 111.

The random access controller 1012 outputs the number of a signature andthe deviation amount of synchronization timing to the radio resourcecontroller 1011 based on the information about the physical randomaccess channel, the number of a signature, and the deviation amount ofsynchronization timing input from the preamble detector 103, and outputsthe same to the radio resource controller 1011 so as to generate arandom access response. Moreover, the random access controller 1012calculates the RA-RNTI from the information about the physical randomaccess channel having detected the signature input from the preambledetector 103, and outputs the same to the radio resource controller1011.

The random access controller 1012, based on the information about thephysical random access channel having detected the signature input fromthe preamble detector 103, selects a downlink carrier component pairedwith an uplink carrier component in which a preamble has been detected,and outputs the same to the radio resource controller 1011 so as totransmit a random access response by means of the selected downlinkcarrier component. Moreover, the random access controller 1012 selectsan uplink carrier component in which the preamble has been detected, andoutputs control information to the radio resource controller 1011 so asto allocate, among the radio resources of the selected uplink carriercomponent, a radio resource for transmitting Message 3.

The random access controller 1012 outputs control information to theradio resource controller 1011 so as to transmit, by means of a downlinkcarrier component, contention resolution to the mobile station apparatus1 to which the radio resource has been allocated by means of the randomaccess response, the mobile station apparatus 1 having transmittedMessage 3.

The controller 107, based on the control information from the higherlayer processor 101, generates a control signal for controlling thereception processor 109 and the transmission processor 111. Thecontroller 107 outputs the generated control signal to the receptionprocessor 109 and the transmission processor 111, and controls thereception processor 109 and the transmission processor 111.

The reception processor 109, in accordance with the control signal inputfrom the controller 107, separates, demodulates and decodes a receptionsignal received from the mobile station apparatus 1 via the receivingantenna, and outputs the decoded information to the higher layerprocessor 101. Moreover, the reception processor 109 outputs theseparated uplink reference signal to the synchronization timingmeasurement unit 105, and outputs the separated physical random accesschannel to the preamble detector 103.

Specifically, the reception processor 109 converts (down-converts) thesignal of each uplink carrier component, which is received via eachreceiving antenna, into an intermediate frequency, removes an unwantedfrequency component, and controls an amplification level so that thesignal level is adequately maintained, and orthogonally demodulates areceived signal based on the in-phase component and quadrature componentof the received signal, and converts the orthogonally demodulated analogsignal into a digital signal. The reception processor 109 removes theportion corresponding to a guard interval (GI) from the converteddigital signal. The reception processor 109 performs Fast FourierTransform (FFT) on the signal, from which the guard interval has beenremoved, to extract a signal in the frequency domain.

The reception processor 109 separates the extracted signal into thesignals arranged in a physical random access channel, in a physicaluplink control channel, in a physical uplink shared channel, in ademodulation reference signal, and in a sounding reference signal,respectively, for each uplink carrier component. Note that thisseparation is performed based on the radio resource allocationinformation which the base station apparatus 3 determined in advance andnotified to each mobile station apparatus 1. Moreover, the receptionprocessor 109 calculates, from the separated uplink reference signal, anestimated value of a channel and performs compensation of the channelsof the physical uplink control channel and the physical uplink sharedchannel.

The reception processor 109 outputs the separated physical random accesschannel to the preamble detector 103, and outputs the separated uplinkreference signal to the synchronization timing measurement unit 105. Thereception processor 109 performs Inverse Discrete Fourier Transform(IDFT) on the physical uplink shared channel to obtain a modulationsymbol. Then, with respect to the respective modulation symbols of thephysical uplink control channel and the physical uplink shared channel,the reception processor 109 demodulates the reception signal using apredetermined modulation scheme, such as binary phase shift keying(BPSK), quadrature phase shift keying (QPSK), 16 quadrature amplitudemodulation (16QAM), or 64 quadrature amplitude modulation (64QAM), orusing a modulation scheme which the base station apparatus 3 notified tothe respective mobile station apparatuses 1 in advance by means of theuplink grant.

The reception processor 109 decodes the demodulated coded-bit of thephysical uplink control channel and the physical uplink shared channelat a predetermined coding rate of a predetermined coding scheme or at apredetermined coding rate, which the base station apparatus 3 notifiedthe mobile station apparatuses 1 in advance by means of an uplink grant,of a predetermined coding scheme, and outputs the data information andthe uplink control information to the higher layer processor 101. Thereception processor 109 measures the power and the like of the receptionsignal of the uplink reference signal or the physical uplink sharedchannel received from the mobile station apparatus 1 to measure thechannel reception quality of the uplink carrier component, and outputsthe same to the higher layer processor 101.

The preamble detector 103 detects a plurality of preambles from theradio resource of a physical random access channel input from thereception processor 109, calculates a synchronization timing deviationamount from the respective preambles, and outputs the information aboutthe physical random access channel in which a signature has beendetected, the number of a signature, and the synchronization timingdeviation amount to the higher layer processor 101. Moreover, from thenumber of times of reception of preambles, the preamble detector 103also periodically notifies the higher layer processor 101 of the randomaccess transmission conditions of the mobile station apparatus 1. Thesynchronization timing measurement unit 105 measures the uplinkreference signal input from the reception processor 109 for the purposeof maintaining synchronization, measures the deviation insynchronization timing, and reports the measurement result to the higherlayer processor 101.

The transmission processor 111, in accordance with the control signalinput from the controller 107, generates a downlink reference signal,encodes and demodulates the data information and downlink controlinformation input from the higher layer processor 101, arranges thesedemodulated information into a physical downlink control channel and aphysical downlink shared channel, multiplexes the same with thegenerated downlink reference signal, and transmits the resulting signalto the mobile station apparatus 1 via the transmission antenna.

Specifically, the transmission processor 111, in accordance with thecontrol signal input from the controller 107, performs encoding, such asturbo encoding, convolutional encoding, or block encoding, on thedownlink control information and data information of the respectivedownlink carrier components input from the higher layer processor 101,and then modulates the encoded bit using a modulation scheme, such asQPSK, 16QAM, or 64QAM. Moreover, the transmission processor 111generates, as the downlink reference signal, a sequence calculated by arule which is predetermined based on a cell identifier (Cell ID) and thelike for identifying the base station apparatus 3, the sequence beingknown by the base station apparatus 3, and multiplexes the downlinkreference signal with the physical downlink control channel signal andthe physical downlink shared channel signal.

The transmission processor 111 performs Inverse Fast Fourier Transform(IFFT) on the multiplexed modulation symbol, and performs OFDMmodulation on the resulting symbol, adds a guard interval to theOFDM-modulated OFDM symbol, and generates a baseband digital signal,converts the baseband digital signal into an analog signal, generatesthe in-phase component and quadrature component of an intermediatefrequency from the analog signal, removes the redundant frequencycomponents with respect to the intermediate frequency band, converts(up-converts) the intermediate frequency signal into a high frequencysignal, removes the redundant frequency components, and power-amplifiesthe resulting high frequency signal, and outputs the amplified signal tothe transmission antenna for transmission.

FIG. 7 is a schematic block diagram showing the configuration of themobile station apparatus 1 according to the embodiment. As shown in theview, the mobile station apparatus 1 comprises a higher layer processor201, a controller 203, a reception processor 205, a plurality ofreceiving antennas, a preamble generator 207, a transmission processor209, and a plurality of transmission antennas. Moreover, the higherlayer processor 201 comprises a radio resource controller 2011 and arandom access processor 2012. Note that, in FIG. 7, the receivingantennas and the transmission antennas are separately configured, butthe antennas may be shared using a thyristor or the like capable ofswitching the input/output of a signal.

The higher layer processor 201 outputs the data information for eachuplink carrier component generated by the operation of a user or thelike to the transmission processor 209. Moreover, the higher layerprocessor 201 performs the processing of a packet data convergenceprotocol layer, a radio link control layer, and a radio resource controllayer. The radio resource controller 2011 of the higher layer processor201 performs the management and the like of the various kinds ofconfiguration data, communication conditions, and buffer conditions ofthe mobile station apparatus 1. The random access processor 2012 of thehigher layer processor 201 performs the control related to the randomaccess of the mobile station apparatus 1.

In the above-described processing, the radio resource controller 2011 ofthe higher layer processor 201 manages the downlink carrier componentand uplink carrier component allocated to the mobile station apparatus1, and various kinds of configuration data such as C-RNTI. Moreover, theradio resource controller 2011 generates the information to be arrangedin each channel of each uplink carrier component, and outputs the sameto the transmission processor 209 for each uplink carrier component. Forexample, when the radio resource for Message 3 is allocated by a randomaccess response, the radio resource controller 2011 generates theinformation to be transmitted by Message 3 and outputs the same to thetransmission processor 209.

Based on the downlink control information (e.g., downlink grant, uplinkgrant) notified by means of the physical downlink control channel fromthe base station apparatus 3, the uplink grant with respect to theMessage 3 notified by random access, and various kinds of configurationdata of the mobile station apparatus 1 managed by the radio resourcecontroller 2011, the radio resource controller 2011 generates controlinformation in order and controls the reception processor 205 and thetransmission processor 209, and outputs the same to the controller 203.

In the above-described processing, the random access processor 2012 ofthe higher layer processor 201 manages: information related to randomaccess transmission, which the base station apparatus 3 broadcasts, suchas information indicative of a pair of an uplink carrier component and adownlink carrier component for transmitting/receiving some of or all ofthe messages, the messages being related to random access, theconfiguration of the physical random access channel, which the downlinkcarrier component corresponds to, and the transmission conditions ofrandom access; and information indicative of the physical random accesschannel corresponding to a specific downlink carrier component, by meansof which random access procedure can be started, notified from the basestation apparatus 3. The random access processor 2012 starts randomaccess when the mobile station apparatus 1 has received a physicaldownlink control channel instructing to start random access procedurefrom the base station apparatus 3 and when there is data information tobe transmitted by means of an uplink but the uplink radio resource hasnot been allocated from the base station apparatus 3.

When the random access processor 2012 is instructed to start randomaccess by means of a physical downlink control channel from the basestation apparatus 3 and the number of a signature and the radio resourceof the physical random access channel corresponding to a downlinkcarrier component are specified, the random access processor 2012selects, among the radio resources of the physical random access channelcorresponding to a specific downlink carrier component set in the basestation apparatus 3, the physical random access channel and signaturewhich are specified by the physical downlink control channel instructingto start random access procedure.

Moreover, when the number of a signature and the radio resource of aphysical random access channel have not been specified by means of thephysical downlink control channel instructing to start random accessprocedure, or when the random access processor 2012 has determined tostart random access procedure, the random access processor 2012 randomlyselects a radio resource among the radio resources of the physicalrandom access channel corresponding to a specific downlink carriercomponent, by means of which the random access procedure can be started,set in the base station apparatus 3, and determines, from theinformation about the downlink channel quality and the like, a range ofsignatures for contention based random access to select, and thenrandomly selects a signature from the selected range of signatures.Thus, the mobile station apparatus 1 can perform contention based randomaccess by means of an appropriate random access resource correspondingto a specific downlink carrier component, which the base stationapparatus 3 preliminarily allocated based on the channel quality of anuplink carrier component, the transmission conditions of a physicalrandom access channel, and the like.

The random access processor 2012 outputs control information to thecontroller 203 so that the preamble generator 207 generates a preambleincluding the selected signature, and outputs the control information tothe controller 203 so that the transmission processor 209 transmits thepreamble by means of the radio resource of the selected physical randomaccess channel.

The random access processor 2012 calculates the RA-RNTI corresponding tothe radio resource, by means of which the preamble has been transmitted.Moreover, the random access processor 2012 outputs control informationto the controller 203 so that the reception processor 205 monitors thedownlink grant including the calculated RA-RNTI in the downlink carriercomponent paired with the uplink carrier component, by means of whichthe preamble has been transmitted, during a random access responsereceiving period which is a predetermined period after transmitting thepreamble.

When the number of a signature is specified from the base stationapparatus 3, and if the number of a signature specified from the basestation apparatus 3 is included in the random access response in whichthe downlink grant including the calculated RA-RNTI indicates theallocation of radio resources, the random access processor 2012determines that random access is successful, and terminates theprocessing related to the random access procedure.

When the number of a signature has not been specified from the basestation apparatus 3, the random access processor 2013 detects, from therandom access response in which the downlink grant including thecalculated RA-RNTI indicates the allocation of radio resources, thenumber of a signature included in the preamble which the mobile stationapparatus 1 transmitted, and obtains a deviation amount ofsynchronization timing, the temporary C-RNTI, and the uplink grantindicative of the allocation of radio resources of Message 3corresponding to the number of the detected signature. Moreover, therandom access processor 2012, based on the deviation amount ofsynchronization timing, outputs control information to the controller203 so as to adjust the transmission timing of the uplink signal of thetransmission processor 209.

The random access processor 2012 outputs the uplink grant addressed tothe mobile station apparatus 1, the uplink grant being included in therandom access response, to the radio resource controller 2011. Moreover,the random access processor 2012 outputs control information to theradio resource controller 2011 so as to generate Message 3 including theC-RNTI allocated to the base station apparatus 3 or the information suchas a connection request.

The random access processor 2012 monitors contention resolution in thedownlink carrier component allocated to the base station apparatus 3during a contention resolution receiving period which is a predeterminedperiod after transmitting Message 3, and determines, if the contentionresolution has been detected in the downlink carrier component, thatrandom access is successful and terminates the processing related to therandom access.

The controller 203, based on the control information from the higherlayer processor 201, generates the control signals controlling thereception processor 205, the preamble generator 207, and thetransmission processor 209. The controller 203 outputs the generatedcontrol signals to the reception processor 205, the preamble generator207, and the transmission processor 209 and controls the receptionprocessor 205, the preamble generator 207, and the transmissionprocessor 209.

The reception processor 205, in accordance with the control signal inputfrom the controller 203, separates, demodulate and decodes the receptionsignal received from the base station apparatus 3 via the receivingantenna, and outputs the decoded information to the higher layerprocessor 201. Moreover, the reception processor 205, based on thereception quality and the like of the detected downlink referencesignal, generates channel quality information and outputs the same tothe higher layer processor 201 and the transmission processor 209.

Specifically, the reception processor 205 converts (down-converts) thesignal of each uplink carrier component, which has been received viaeach receiving antenna, into an intermediate frequency, removes anunwanted frequency component, and controls an amplification level sothat the signal level is adequately maintained, and orthogonallydemodulates the received signal based on the in-phase component andquadrature component of the received signal, and converts theorthogonally demodulated analog signal into a digital signal. Thereception processor 205 removes the portion corresponding to a guardinterval from the converted digital signal. The reception processor 205performs Fast Fourier Transform on the signal, from which the guardinterval has been removed, to extract a frequency domain signal.

The reception processor 205 separates the extracted signal for eachdownlink carrier component into the signals arranged in a physicaldownlink control channel, in a physical downlink shared channel, and inthe downlink reference signal, respectively. Note that this separationis performed based on the radio resource allocation information and thelike notified by downlink grant. Moreover, the reception processor 205calculates an estimated value of a channel from the separated downlinkreference signal, and performs compensation of the channels of aphysical downlink control channel and a physical downlink sharedchannel. Moreover, the reception processor 205, based on the receptionquality and the like of the separated downlink reference signal,generates channel quality information and outputs the same to the higherlayer processor 201 and the transmission processor 209.

The reception processor 205 performs demodulation of the QPSK modulationscheme on a physical downlink control channel, and monitors the downlinkgrant and uplink grant including the C-RNTI which is allocated to themobile station apparatus by the base station apparatus 3 and thedownlink grant including the RA-RNTI corresponding to the radio resourceof the physical random access channel, by means of which the mobilestation apparatus transmitted the preamble, and attempts to decode. Thereception processor 205, if succeeded in decoding a physical downlinkcontrol channel, outputs the decoded downlink control information to thehigher layer processor 201. The reception processor 205 performs thedemodulation of a modulation scheme, such as QPSK, 16QAM, or 64QAM,which is notified by downlink grant, on a physical downlink sharedchannel, and performs the decoding corresponding to a coding ratenotified by downlink grant, and outputs the decoded data information tothe higher layer processor 201.

The preamble generator 207, in accordance with the control signal inputfrom the controller 203, generates the preamble including the signaturewhich the random access processor 2012 has selected, and outputs thesame to the transmission processor 209.

The transmission processor 209, in accordance with the control signalinput from the controller 203, generates an uplink reference signal,encodes and modulates the data information input from the higher layerprocessor 201 and the channel quality information input from thereception processor 205, and arranges the resulting information into aphysical uplink shared channel and in a physical uplink control channel,and multiplexes the same with the generated uplink reference signal andtransmits the multiplexed signal to the base station apparatus 3 via thetransmission antenna. Moreover, the transmission processor 209, inaccordance with the control signal input from the controller 203,arranges the preamble, which is input from the preamble generator 207,into a physical random access channel and transmits the same to the basestation apparatus 3 via the transmission antenna.

Specifically, the transmission processor 209, in accordance with thecontrol signal input from the controller 203, performs encoding, such asturbo encoding, convolutional encoding, block encoding, on the uplinkcontrol information and data information of each uplink carriercomponent input from the higher layer processor 201 and the receptionprocessor 205, and modulates the encoded bit with a modulation scheme,such as BPSK, QPSK, 16QAM, or 64QAM.

The transmission processor 209 generates, as an uplink reference signal,a sequence calculated by a rule which is predetermined based on a cellidentifier and the like for identifying the base station apparatus 3,the sequence being known by the base station apparatus 3. Thetransmission processor 209 spreads the modulation symbol of a physicaluplink control channel with a code, and rearranges the modulationsymbols of the physical uplink shared channel in parallel, and thenperforms Discrete Fourier Transform (DFT) on the rearranged modulationsymbols, and multiplexes the resulting modulation symbols with thegenerated uplink reference signal. Moreover, the transmission processor209 arranges the preamble, which is input from the preamble generator207, into a physical random access channel.

The transmission processor 209 performs Inverse Fast Fourier Transformon the multiplexed signal, and performs the modulation of SC-FDMA, andadds a guard interval to the SC-FDMA modulated SC-FDMA symbol andgenerates a baseband digital signal, converts the baseband digitalsignal into an analog signal, generates the in-phase component andquadrature component of an intermediate frequency from the analogsignal, removes the redundant frequency components with respect to theintermediate frequency band, converts (up-converts) an intermediatefrequency signal into a high frequency signal, removes the redundantfrequency components, power-amplifies the resulting high frequencysignal, and outputs the amplified signal to the transmission antenna fortransmission.

Hereinafter, the operation of a wireless communication system isdescribed. FIG. 8 is a conceptual view showing the relationship betweena physical downlink control channel and a physical random access channelaccording to the embodiment. FIG. 8 shows a case where the base stationapparatus 3 allocates three downlink carrier components (DCC-1, DCC-2,DCC-3) and three uplink carrier components (UCC-1, UCC-2, UCC-3) to themobile station apparatus 1 and allocates UCC-2 as the uplink carriercomponent which the physical downlink control channel instructing tostart the physical random access channel corresponds to.

In FIG. 8, the base station apparatus 3 notifies the mobile stationapparatus 1 of the physical random access channel of UCC-2, which DCC-2corresponds to, as the physical random access channel by means of whichrandom access procedure can be started. Moreover, the base stationapparatus 3 allocates the radio resource of the physical random accesschannel of UCC-2 and the number of a signature to the mobile stationapparatus 1, and transmits the physical downlink control channelinstructing to start the random access procedure, the physical downlinkcontrol channel including the information indicative of the allocatedphysical random access channel and number of a signature, by means ofany one downlink carrier component among the downlink carrier components(DCC-1, DCC-2, DCC-3) allocated to the mobile station apparatus 1.

Upon receipt of the physical downlink control channel instructing tostart random access procedure by means of any one downlink carriercomponent among the downlink carrier components (DCC-1, DCC-2, DCC-3)allocated to the base station apparatus 3, the mobile station apparatus1 transmit a preamble (Message 1) using the radio resource of a physicalrandom access channel and the signature, which the relevant physicaldownlink control channel indicates, among the physical random accesschannels of UCC-2 notified from the base station apparatus 3.

FIG. 9 is a flow diagram showing an example of the operation of the basestation apparatus 3 according to the embodiment. The base stationapparatus 3 allocates to the mobile station apparatus 1 a downlinkcarrier component, by means of which a physical downlink shared channelmay be transmitted, and an uplink carrier component to which the radioresource of a physical uplink shared channel may be allocated (StepS10). The base station apparatus 3 allocates to the mobile stationapparatus 1 physical random access channels corresponding to a specificdownlink carrier component by means of which random access procedure canbe started, and notifies the information indicative of this allocationto the mobile station apparatus 1 (Step S11). The base station apparatus3 transmits the physical downlink control channel instructing to startrandom access procedure to the mobile station apparatus 1 by means ofany one downlink carrier component (Step S12). After Step S12, the basestation apparatus 3 terminates the processing related to thetransmission of the physical downlink control channel instructing tostart random access procedure.

FIG. 10 is a flow diagram showing an example of the operation of themobile station apparatus 1 according to the embodiment. The mobilestation apparatus 1 is allocated, from the base station apparatus 3, adownlink carrier component to which a physical downlink shared channelmay be transmitted and an uplink carrier component to which the radioresource of a physical uplink shared channel may be allocated (StepS20). The mobile station apparatus 1 is notified of the informationindicative of the physical random access channels corresponding to aspecific downlink carrier component, by means of which random accessprocedure can be started, the physical random access channels beingallocated from the base station apparatus (Step S21).

The mobile station apparatus 1 receives the physical downlink controlchannel instructing to start random access procedure by means of any onedownlink carrier component among the downlink carrier componentsallocated in Step S20 (Step S22). The mobile station apparatus 1 startsrandom access procedure by means of the physical random access channelcorresponding to a specific downlink carrier component, by means ofwhich random access procedure can be started, allocated in Step S21(Step S23). After Step S23, the mobile station apparatus 1 terminatesthe processing related to the reception of the physical downlink controlchannel instructing to start random access procedure.

Note that, in the first embodiment of the present invention, because adownlink carrier component and an uplink carrier component, by means ofwhich the base station apparatus 3 and the mobile station apparatus 1transmit/receive some of or all of the messages for random access, serveas a pair, the base station apparatus 3 allocates to the mobile stationapparatus 1 physical random access channels corresponding to a specificdownlink carrier component, by means of which random access procedurecan be started, in other words the base station apparatus 3 allocates tothe mobile station apparatus 1 a downlink carrier component and anuplink carrier component, by means of which communication for randomaccess procedure can be performed, and the base station apparatus 3allocates to the mobile station apparatus 1 a downlink carrier componentor an uplink carrier component by means of which the communications forrandom access procedure can be performed.

Thus, according to the first embodiment of the present invention, thewireless communication system is a wireless communication system inwhich the base station apparatus 3 and at least one mobile stationapparatus 1 communicate with each other using a plurality of carriercomponents each defined by a different frequency band, wherein the basestation apparatus 3 preliminarily allocates random access resourcescorresponding to a specific downlink carrier component, by means ofwhich the mobile station apparatus 1 can start a random accesscommunication, among the random access resources corresponding to therespective downlink carrier components set in the mobile stationapparatus 1, and transmits a physical downlink control channel (controlinformation) instructing to start random access procedure by means ofone arbitrary downlink carrier component among a plurality of downlinkcarrier components set in the mobile station apparatus 1, and whereinupon receipt of the physical downlink control channel (controlinformation) instructing to start random access procedure by means ofany one downlink carrier component, the mobile station apparatus 1starts random access procedure by means of the random access resourcecorresponding to a specific downlink carrier component preliminarilyallocated to the base station apparatus 3.

In this manner, without changing the configuration of the physicaldownlink control channel instructing to start the random accessprocedure in the conventional art, the mobile station apparatus 1 candetermine that “the physical downlink control channel instructing tostart random access procedure, the physical downlink control channelbeing received by means of any one downlink carrier component among aplurality of downlink carrier components allocated from the base stationapparatus 3, is indicating the start of random access procedure withrespect to a random access resource corresponding to a preliminarilyallocated specific downlink carrier component.” Moreover, the basestation apparatus 3, based on the channel quality of a plurality ofdownlink carrier components allocated to the mobile station apparatus 1,the overhead of a physical downlink control channel, and the like, canflexibly select a downlink carrier component in which the physicaldownlink control channel instructing to start random access procedure isarranged.

Second Embodiment

Hereinafter, a second embodiment of the present invention will bedescribed with reference to the accompanying drawings.

In the second embodiment of the present invention, a case is describedwhere a base station apparatus selects, from among the radio resourcesof physical random access channels corresponding to a plurality ofdownlink carrier components allocated to a mobile station apparatus, onearbitrary physical random access channel for instructing the mobilestation apparatus to start physical random access channel processing,and indicates “which downlink carrier component the selected physicalrandom access channel corresponds to” to the mobile station apparatus bymeans of the downlink carrier component for transmitting a physicaldownlink control channel instructing to start the random accessprocedure.

Comparing the wireless communication system according to the embodimentwith the wireless communication system according to the firstembodiment, the higher layer processor of the mobile station apparatusand the higher layer processor of the base station apparatus differbetween the first and second embodiments. However, because theconfigurations and functions which other components have are the same asthose of the first embodiment, the description of the same functions asthose of the first embodiment is omitted. Hereinafter, a mobile stationapparatus and a base station apparatus according to the embodiment arereferred to as a mobile station apparatus 5 and a base station apparatus7, respectively.

FIG. 11 is a schematic block diagram showing the configuration of thebase station apparatus 7 according to the second embodiment of thepresent invention. Comparing a higher layer processor 301 (FIG. 11)according to the embodiment with the higher layer processor 101 (FIG. 6)according to the first embodiment, a radio resource controller 3011 anda random access controller 3012 differ.

Now, the processing of the higher layer processor 301 of the basestation apparatus 7 is described. The higher layer processor 3011outputs the data information for each downlink carrier component to thetransmission processor 111. Moreover, the higher layer processor 301performs the processing of a packet data convergence protocol layer, aradio link control layer, and a radio resource control layer. The radioresource controller 3011 of the higher layer processor 301 performs themanagement and the like of various kinds of configuration data,communication conditions, and buffer conditions of the respective mobilestation apparatuses 5. The random access controller 3012 of the higherlayer processor 301 performs the control related to random access of therespective mobile station apparatuses 5.

Comparing the radio resource controller 3011 according to the embodimentwith the radio resource controller 1011 according to the firstembodiment, a difference is in that the radio resource controller 3011selects one downlink carrier component based on the control informationfrom the random access controller 3012 and transmits a physical downlinkcontrol channel instructing to start random access procedure to themobile station apparatus 5 via the transmission processor 111 by meansof the selected downlink carrier component. Because other functionswhich the radio resource controller 3011 according to the embodiment hasare the same as those which the radio resource controller 1011 accordingto the first embodiment has, the description of the same functions asthose of the first embodiment is omitted.

The random access controller 3012 generates broadcast informationincluding the information related to random access, such as informationindicative of a pair of an uplink carrier component and a downlinkcarrier component for transmitting/receiving some of or all of themessages for random access, the configuration of a physical randomaccess channel (the allocation and the like of radio resources of aphysical random access channel), the transmission conditions (randomaccess load) of random access, and additionally a pair of physicalrandom access channels corresponding to a downlink carrier component fortransmitting a physical downlink control channel instructing to startthe random access procedure and a downlink carrier component to beinstructed to start random access procedure. The random accesscontroller 3012 then outputs control information to the radio resourcecontroller 3011 so as to transmit the same to the mobile stationapparatus 5 via the transmission processor 111.

For example, when the base station apparatus 7 and the mobile stationapparatus 5 are out of synchronization while the random accesscontroller 3012 has data information to be transmitted to the mobilestation apparatus 5, the random access controller 3012 determines toinstruct the mobile station apparatus 5 to start random accessprocedure. Moreover, the random access controller 3012, based on thetransmission conditions of random access, the channel quality of theuplink carrier component, and the like, selects an uplink carriercomponent instructing to start random access procedure and allocates theradio resource of a physical random access channel and the signaturewithin the selected uplink carrier component to the mobile stationapparatus 5.

The random access controller 3012 generates the physical downlinkcontrol channel for instructing the mobile station apparatus 5 to startrandom access procedure, and outputs control information to the radioresource controller 3011 so as to transmit the relevant physicaldownlink control channel to the mobile station apparatus 5 via thetransmission processor 111 by means of the downlink carrier componentcorresponding to the physical random access channel of the uplinkcarrier component instructing to start random access procedure.

Moreover, the random access controller 3012 according to the embodimentdoes not have the function which the random access controller 1012according to the first embodiment has, i.e., the function to set to therespective mobile station apparatuses 1 a physical random access channelcorresponding to a specific downlink carrier component, by means ofwhich random access procedure can be started, based on the transmissionconditions of random access, the channel quality of the uplink carriercomponent, and the like, generate information indicative of the setspecific downlink carrier component, and include this information into aradio resource control signal and the like, and output the resultingcontrol information to the radio resource controller 1011 so as totransmit the same to the respective mobile station apparatuses 1 via thetransmission processor 111. Because other functions which the radioresource controller 3011 according to the embodiment has are the same asthose which the radio resource controller 1011 according to the firstembodiment has, the description of the same functions as those of thefirst embodiment is omitted.

FIG. 12 is a schematic block diagram showing the configuration of themobile station apparatus 5 according to the second embodiment of thepresent invention. Comparing an higher layer processor 401 (FIG. 12)according to the embodiment with the higher layer processor 201 (FIG. 7)according to the first embodiment, a random access processor 4012differs.

The higher layer processor 401 outputs the data information for eachuplink carrier component generated by the operation of a user or thelike to the transmission processor 209. Moreover, the higher layerprocessor 401 performs the processing of a packet data convergenceprotocol layer, a radio link control layer, and a radio resource controllayer. The random access processor 4012 of the higher layer processor401 performs the control related to the random access of the mobilestation apparatus 5.

In the above-described processing, when the mobile station apparatusreceives a physical downlink control channel instructing to start therandom access procedure from the base station apparatus 3 and when thereis data information to be transmitted by means of an uplink but theuplink radio resource has not been allocated from the base stationapparatus 3, the random access processor 4012 of the higher layerprocessor 401 starts random access procedure.

The random access processor 4012, upon receipt of a physical downlinkcontrol channel instructing to start random access procedure by any onedownlink carrier component, determines that the random access processor4012 is instructed to start the random access procedure by means of theradio resource of a physical random access channel which a downlinkcarrier component corresponds to, the downlink carrier component havingreceiving the relevant physical downlink control channel. Moreover, therandom access processor 4012 selects the number of a signature specifiedby the relevant physical downlink control channel, and the radioresource of the physical random access channel.

When the number of a signature and the radio resource of the physicalrandom access channel have not been specified by means of the physicaldownlink control channel instructing to start the random accessprocedure, or when the random access processor 4012 has determined tostart random access procedure, the random access processor 4012 randomlyselects an uplink carrier component and the radio resource of a physicalrandom access channel within the uplink carrier component. Furthermore,the random access processor 4012 determines, from the channel qualityinformation and the like of the downlink carrier component, a range ofsignatures for contention based random access to select, and randomlyselects a signature from the selected range of signatures. Thus, themobile station apparatus 5 selects the random access resource forperforming contention based random access, from the random accessresources corresponding to all the downlink carrier components allocatedto the base station apparatus 7. Therefore, the random access resourceswhich a plurality of mobile station apparatus 5 select are dispersed,and the probability that a plurality of mobile station apparatus 5select the same random access resource and the same number of asignature can be reduced.

The random access processor 4012 according to the embodiment does nothave the function, which the random access processor 2012 according tofirst embodiment has, i.e., the function to manage the informationindicative of a physical random access channel corresponding to aspecific downlink carrier component by means of which random accessprocedure can be started. Because other functions which the randomaccess processor 4012 according to the embodiment has are the same asthose which the random access processor 2012 according to the firstembodiment has, the description of the same functions as those of thefirst embodiment is omitted.

Hereinafter, the operation of a wireless communication system isdescribed. FIG. 13 is a conceptual view showing the relationship betweena physical downlink control channel and a physical random access channelaccording to the embodiment. FIG. 13 shows a case where the base stationapparatus 7 allocates three downlink carrier components (DCC-1, DCC-2,DCC-3) and three uplink carrier components (UCC-1, UCC-2, UCC-3) to themobile station apparatus 5, and notifies that DCC-1 and UCC-1, DCC-2 andUCC-2, DCC-3 and UCC3 each are pairs as the pair of a downlink carriercomponent for transmitting a physical downlink control channelinstructing to start the random access procedure and an uplink carriercomponent including a physical random access channel to be instructed tostart random access procedure.

In FIG. 13, the base station apparatus 7 allocates the radio resource ofa physical random access channel and the number of a signature of UCC1,UCC-2, or UCC-3 to the mobile station apparatus 5, and transmits aphysical downlink control channel instructing to start the random accessprocedure by means of the downlink carrier component (DCC-1, DCC-2,DCC-3) which the radio resource of the physical random access channelallocated to the mobile station apparatus 5 corresponds to.

Upon receipt of the physical downlink control channel instructing tostart the random access procedure by means of any one downlink carriercomponent among the downlink carrier components (DCC-1, DCC-2, DCC-3)allocated to the base station apparatus 7, the mobile station apparatus5 selects a physical random access channel corresponding to the downlinkcarrier component (DCC-1, DCC-2, DCC-3) having received the relevantphysical downlink control channel, and transmits the preamble(Message 1) using the radio resource and signature of the physicalrandom access channel which the relevant physical downlink controlchannel indicates by means of the selected uplink carrier component.

FIG. 14 is a flow diagram showing an example of the operation of thebase station apparatus 7 according to the embodiment. The base stationapparatus 7 allocates to the mobile station apparatus 5 a downlinkcarrier component by means of which a physical downlink shared channelmay be transmitted, and an uplink carrier component to which the radioresource of a physical uplink shared channel may be allocated (StepS30). The base station apparatus 7 notifies the mobile station apparatus5 of the information indicative of a pair of physical random accesschannels corresponding to a downlink carrier component for transmittinga physical downlink control channel instructing to start the randomaccess procedure and a downlink carrier component to be instructed tostart random access procedure (Step 31).

The base station apparatus 7 selects a physical random access channelcausing the mobile station apparatus 5 to start random access procedure(Step S32). The base station apparatus 7 transmits to the mobile stationapparatus 5 a physical downlink control channel instructing to start therandom access procedure by means of the downlink carrier componentcorresponding to the physical random access channel selected in Step S32(Step S33). After Step S33, the base station apparatus 7 terminates theprocessing related to the transmission of the physical downlink controlchannel instructing to start the random access procedure.

FIG. 15 is a flow diagram showing an example of the operation of themobile station apparatus 5 according to the embodiment. The mobilestation apparatus 5 is allocated, from the base station apparatus 7, adownlink carrier component to which a physical downlink shared channelmay be transmitted and an uplink carrier component to which the radioresource of a physical uplink shared channel may be allocated (StepS40). The mobile station apparatus 5 obtains, from the base stationapparatus 7, the information indicative of a pair of physical randomaccess channels corresponding to a downlink carrier component fortransmitting a physical downlink control channel instructing to startthe random access procedure and a downlink carrier component to beinstructed to start random access procedure (Step S41).

The mobile station apparatus 5 receives the physical downlink controlchannel instructing to start the random access procedure by means of anyone downlink carrier component among the downlink carrier componentsallocated in Step S40 (Step S42). Upon receipt of the physical downlinkcontrol channel instructing to start the random access procedure, themobile station apparatus 5 determines, in accordance with theinformation obtained in Step S41, that the mobile station apparatus 5 isinstructed to start the random access procedure in the physical randomaccess channel corresponding to a downlink carrier component, by meansof which the relevant physical downlink control channel has beenreceived, and starts the random access procedure by means of therelevant physical random access channel (Step S43). After Step S43, themobile station apparatus 5 terminates the processing related to thereception of the physical downlink control channel instructing to startthe random access procedure.

Note that, in the second embodiment of the present invention, the basestation apparatus 7 transmits information indicative of a pair of anuplink carrier component and a downlink carrier component fortransmitting/receiving some of or all of the messages, and informationindicative of a pair of physical random access channels corresponding toa downlink carrier component for transmitting a physical downlinkcontrol channel instructing to start the random access procedure and adownlink carrier component to be instructed to start random accessprocedure. However, the pair of an uplink carrier component and adownlink carrier component for transmitting/receiving some of or all ofthe messages may be set the same as the pair of physical random accesschannels corresponding to a downlink carrier component for transmittinga physical downlink control channel instructing to start random accessprocedure, and a downlink carrier component to be instructed to startrandom access procedure. Thus, the mobile station apparatus 5, uponreceipt of a physical downlink control channel instructing to start therandom access procedure by means of any one downlink carrier component,may determine that the mobile station apparatus 5 is instructed to startrandom access procedure by means of the physical random access channelcorresponding to the relevant downlink carrier component, so that theamount of information which the base station apparatus 7 broadcasts canbe reduced.

Thus, according to the second embodiment of the present invention, thewireless communication system is a wireless communication system inwhich the base station apparatus 7 and at least one mobile stationapparatus 5 communicate with each other using a plurality of carriercomponents each defined by a different frequency band, wherein the basestation apparatus 7 selects, among the random access resourcescorresponding to the respective downlink component carrier componentsset in the mobile station apparatus 5, a random access resource causingthe mobile station apparatus 5 to start a random access communication,and transmits a physical downlink control channel (control information)instructing to start random access procedure by means of a downlinkcomponent carrier component corresponding to the selected random accessresource, and wherein the mobile station apparatus 5, upon receipt of aphysical downlink control channel (control information) instructing tostart random access procedure by means of any one downlink carriercomponent, starts random access procedure by means of the random accessresource corresponding to a downlink carrier component having receivedthe relevant physical downlink control channel (control information).

Thus, without changing the configuration of the physical downlinkcontrol channel instructing to start the random access procedure in theconventional art, the mobile station apparatus 5, depending on by meansof which downlink carrier component among a plurality of downlinkcarrier components allocated from the base station apparatus 7, thephysical downlink control channel instructing to start random accessprocedure has been received, can determine that “the relevant physicaldownlink control channel is currently instructing to start random accessprocedure with respect to a random access resource corresponding towhich downlink carrier component.” Moreover, the base station apparatus7, based on the channel quality of a plurality of uplink carriercomponents allocated to the mobile station apparatus 5, the transmissionconditions (random access load) of the physical random access channel,and the like, can flexibly select the uplink carrier componentinstructing to start the random access procedure.

Note that, in the first embodiment and second embodiment of the presentinvention, each downlink carrier component corresponds to the physicalrandom access channel within a different uplink carrier component, but aplurality of downlink carrier components may correspond to differentphysical random access channels within the same uplink carriercomponent, or a plurality of downlink carrier components may correspondto the same physical random access channel within the same uplinkcarrier component. In this case, information indicative of the uplinkcarrier component paired with a downlink carrier component, theinformation being included in information related to random accesstransmission of a plurality of downlink carrier components, or theconfiguration of a physical random access channel which the downlinkcarrier component corresponds to becomes the same between the first andsecond embodiments

(A) In addition, the present invention may employ the following forms.That is, the wireless communication system of the present invention is awireless communication system in which the base station apparatus and atleast one mobile station apparatus communicate with each other using aplurality of carrier components each defined by a different frequencyband, wherein the base station apparatus comprises: a random accesscontroller which, among the random access resources corresponding to therespective downlink carrier components set in the mobile stationapparatus 1, preliminarily allocates a random access resourcecorresponding to a specific downlink carrier component by means of whichthe mobile station apparatus 1 can start a random access communication;and a transmission processor which transmits control informationinstructing to start the random access procedure by means of onearbitrary downlink carrier component among a plurality of downlinkcarrier components set in the mobile station apparatus 1, and whereinthe mobile station apparatus further comprises a random access processorwhich, upon receipt of the control information instructing to startrandom access procedure by means of any one downlink carrier component,starts random access procedure by means of the random access resourcecorresponding to a specific downlink carrier component preliminarilyallocated to the base station apparatus.

In this manner, a base station apparatus preliminarily notifies to amobile station that the physical downlink control channel instructing tostart the random access procedure instructs the start of random accessprocedure with respect to the random access resource corresponding towhich downlink carrier component. Therefore, the mobile stationapparatus can determine that a physical downlink control channelinstructing to start the random access procedure, which is received byany one downlink carrier component among a plurality of downlink carriercomponents allocated from the base station apparatus, is currentlyinstructing the start of random access procedure with respect to arandom access resource corresponding to a preliminarily allocatedspecific downlink carrier component. Moreover, the base stationapparatus, based on the channel quality of a plurality of downlinkcarrier components allocated to the mobile station apparatus, theoverhead of a physical downlink control channel, or the like, canflexibly select a downlink carrier component in which a physicaldownlink control channel instructing to start the random accessprocedure is arranged.

(B) The radio communication of the present invention is a wirelesscommunication system in which the base station apparatus and at leastone mobile station apparatus communicate with each other using aplurality of carrier components each defined by a different frequencyband, wherein the base station apparatus comprises a random accesscontroller which, from among the random access resources correspondingto the respective downlink carrier components set in the mobile stationapparatus, selects a random access resource causing the mobile stationapparatus to start a random access communication; and a transmissionprocessor which transmits control information instructing to startrandom access procedure by means of a downlink carrier componentcorresponding to the selected random access resource, and wherein themobile station apparatus further comprises a random access processorwhich, upon receipt of the control information instructing to startrandom access procedure by means of any one downlink carrier component,starts random access procedure by means of a random access resourcecorresponding to the downlink carrier component having received thecontrol information.

In this manner, a base station apparatus notifies the physical downlinkcontrol channel instructing to start the random access procedure to amobile station apparatus by using a downlink carrier component which arandom access resource corresponds to, the random access resource bymeans of which the relevant physical downlink control channel instructsto start random access procedure. Therefore, the mobile stationapparatus, depending on by means of which downlink carrier componentamong a plurality of downlink carrier components allocated from the basestation apparatus, the physical downlink control channel instructing tostart the random access procedure has been received, can determine that“the relevant physical downlink control channel is currently instructingto start random access procedure with respect to the random accessresource corresponding to which downlink carrier component.” Moreover,the base station apparatus, based on the channel quality of a pluralityof uplink carrier components allocated to the mobile station apparatus,the transmission conditions (random access load) of the physical randomaccess channel, and the like, can flexibly select the uplink carriercomponent instructing to start the random access procedure.

(C) In the wireless communication system of the present invention, thebase station apparatus and the mobile station apparatus communicatemessages for random access by means of an uplink carrier componentincluding the random access resource, which the base station apparatusselected, and a downlink carrier component corresponding to the uplinkcarrier component.

With this configuration, the amount of information which a base stationapparatus broadcasts to a mobile station apparatus can be reduced.

(D) In the wireless communication system of the present invention, thebase station apparatus transmits a radio resource control signalincluding information indicative of a specific random access resourceallocated to the mobile station apparatus.

In this manner, a base station apparatus notifies a random accessresource preliminarily allocated to a mobile station apparatus, therandom access resource corresponding to a specific downlink carriercomponent which the physical downlink control channel instructing tostart the random access procedure corresponds to. Therefore, the mobilestation apparatus can determine that “a physical downlink controlchannel instructing to start the random access procedure, the physicaldownlink control channel being received by means of any one downlinkcarrier component among a plurality of downlink carrier componentsallocated from the base station apparatus, is instructing to startrandom access procedure with respect to a random access resourcecorresponding to a preliminarily allocated specific downlink carriercomponent.”

(E) In the wireless communication system of the present invention, thephysical downlink control channel instructing to start the random accessprocedure further includes, among the random access resourcescorresponding to the downlink carrier component, information indicativeof a random access resource, by means of which the mobile stationapparatus can start random access procedure, and information indicativeof a signature.

With this configuration, the base station apparatus, depending on thetransmission conditions of random access and the like, can notify therandom access resource, which is allocated among the random accessresources corresponding to a downlink carrier component, and the numberof a signature to a mobile station apparatus by using a physicaldownlink control channel instructing to start the random accessprocedure.

(F) In the wireless communication system of the present invention, therandom access controller, when specifying contention based random accessas a random access method for the mobile station apparatus, sets theinformation indicative of a signature to a specific code point, and therandom access processor, when the information indicative of a signatureis the specific code point, selects contention based random access asthe random access method.

With this configuration, the base station apparatus can, for examplewhen there is no signature for non-contention based random access to beallocated to a mobile station apparatus, instruct a mobile stationapparatus to select contention based random access as the random accessmethod, using a physical downlink control channel instructing to startthe random access procedure.

(G) In the wireless communication system of the present invention, therandom access processor, when contention based random access has beenselected as the random access method, selects a random access resourcefor starting random access procedure among the random access resourcescorresponding to a specific downlink carrier component preliminarilyallocated to the base station apparatus.

With this configuration, the mobile station apparatus can performcontention based random access by means of an appropriate random accessresource corresponding to a specific downlink carrier component, whichthe base station apparatus preliminarily allocated based on the channelquality of an uplink carrier component, the transmission conditions of aphysical random access channel, and the like.

(H) In the wireless communication system of the present invention, therandom access processor, when contention based random access has beenselected as the random access method, selects a random access resourcefor starting random access procedure among all the random accessresources corresponding to the respective downlink carrier componentsset in the base station apparatus.

With this configuration, a mobile station apparatus selects a randomaccess resource for performing contention based random access among therandom access resources corresponding to all the downlink carriercomponents allocated to a base station apparatus. Therefore, the randomaccess resources which a plurality of mobile station apparatuses selectare dispersed, and the probability that a plurality of mobile stationapparatuses select the same random access resource and the same numberof a signature can be reduced.

(I) The base station apparatus of the present invention is a basestation apparatus applied to a wireless communication system in whichthe base station apparatus and at least one mobile station apparatuscommunicate with each other using a plurality of carrier components eachdefined by a different frequency band, wherein the base stationapparatus comprises: a random access controller which, among the randomaccess resources corresponding to the respective downlink carriercomponents set in the mobile station apparatus, preliminarily allocatesa random access resource by means of which the mobile station apparatuscan start a random access communication, and a transmission processorwhich transmits control information instructing to start the randomaccess procedure by means of one arbitrary downlink carrier componentamong a plurality of downlink carrier components set in the mobilestation apparatus 1.

Thus, a base station apparatus preliminarily notifies to a mobilestation that the physical downlink control channel instructing to startthe random access procedure instructs the start of random accessprocedure with respect to the random access resource corresponding towhich downlink carrier component. Therefore, the mobile stationapparatus can determine that “a physical downlink control channelinstructing to start the random access procedure, the physical downlinkcontrol channel being received by means of any one downlink carriercomponent among a plurality of downlink carrier components allocatedfrom the base station apparatus, is currently instructing to startrandom access procedure with respect to a random access resourcecorresponding to a preliminarily allocated specific downlink carriercomponent.” Moreover, the base station apparatus, based on the channelquality of a plurality of downlink carrier components allocated to themobile station apparatus, the overhead of a physical downlink controlchannel, or the like, can flexibly select a downlink carrier componentin which a physical downlink control channel instructing to start therandom access procedure is arranged.

(J) The base station apparatus of the present invention is a basestation apparatus applied to a wireless communication system in whichthe base station apparatus and at least one mobile station apparatuscommunicate with each other using a plurality of carrier components eachdefined by a different frequency band, wherein the base stationapparatus comprises: a random access controller which, among the randomaccess resources corresponding to the respective downlink carriercomponents set in the mobile station apparatus, selects a random accessresource causing the mobile station apparatus to start a random accesscommunication; and a transmission processor which transmits controlinformation instructing to start random access procedure by means of adownlink carrier component corresponding to the selected random accessresource.

In this manner, a base station apparatus notifies the physical downlinkcontrol channel instructing to start the random access procedure to amobile station apparatus by using a downlink carrier component which arandom access resource corresponds to, the random access resource bymeans of which the relevant physical downlink control channel instructsto start random access procedure. Therefore, the mobile stationapparatus, depending on by means of which downlink carrier componentamong a plurality of downlink carrier components allocated from the basestation apparatus, the physical downlink control channel instructing tostart the random access procedure has been received, can determine that“the relevant physical downlink control channel is currently instructingto start random access procedure with respect to the random accessresource corresponding to which downlink carrier component.” Moreover,the base station apparatus, based on the channel quality of a pluralityof uplink carrier components allocated to the mobile station apparatus,the transmission conditions (random access load) of the physical randomaccess channel, and the like, can flexibly select the uplink carriercomponent instructing to start the random access procedure.

(K) The mobile station apparatus of the present invention is a mobilestation apparatus applied to a wireless communication system in whichthe base station apparatus and at least one mobile station apparatuscommunicate with each other using a plurality of carrier components eachdefined by a different frequency band, wherein the mobile stationapparatus comprises a random access processor which, upon receipt of thecontrol information instructing to start random access procedure bymeans of any one downlink carrier component, starts random accessprocedure by means of the random access resource corresponding to aspecific downlink carrier component preliminarily allocated to the basestation apparatus.

Thus, the mobile station apparatus determines that “a physical downlinkcontrol channel instructing to start the random access procedure, thephysical downlink control channel being received by means of any onedownlink carrier component among a plurality of downlink carriercomponents allocated from the base station apparatus, is currentlyinstructing to start random access procedure with respect to a randomaccess resource corresponding to a preliminarily allocated specificdownlink carrier component.” Therefore, the base station apparatus,based on the channel quality of a plurality of downlink carriercomponents allocated to the mobile station apparatus, the overhead of aphysical downlink control channel, or the like, can flexibly select adownlink carrier component in which a physical downlink control channelinstructing to start the random access procedure is arranged.

(L) The mobile station apparatus of the present invention is a mobilestation apparatus applied to a wireless communication system in whichthe base station apparatus and at least one mobile station apparatuscommunicate with each other using a plurality of carrier components eachdefined by a different frequency band, wherein the mobile stationapparatus comprises a random access processor which, upon receipt of thecontrol information instructing to start random access procedure bymeans of any one downlink carrier component, starts random accessprocedure by means of a random access resource corresponding to thedownlink carrier component by means of which the control information hasbeen received.

Thus, the mobile station apparatus, depending on by means of whichdownlink carrier component among a plurality of downlink carriercomponents allocated from the base station apparatus, the physicaldownlink control channel instructing to start the random accessprocedure has been received, determines that “the relevant physicaldownlink control channel is currently instructing to start random accessprocedure with respect to the random access resource corresponding towhich downlink carrier component.” Therefore, the base stationapparatus, based on the channel quality of a plurality of uplink carriercomponents allocated to the mobile station apparatus, the transmissionconditions (random access load) of the physical random access channel,and the like, can flexibly select the uplink carrier componentinstructing to start the random access procedure.

(M) The wireless communication system of the present invention is awireless communication method, wherein a base station apparatus and atleast one mobile station apparatus perform a random access procedureusing a plurality of carrier components each defined by a differentfrequency band, the method comprising the steps of: among random accessresources corresponding to the respective downlink carrier componentsset in the mobile station apparatus, preliminarily allocating a specificrandom access resource by means of which the mobile station apparatuscan start a random access communication; and transmitting controlinformation instructing to start random access procedure by means of onearbitrary downlink carrier component among a plurality of downlinkcarrier components set in the mobile station apparatus.

Thus, a base station apparatus preliminarily notifies to a mobilestation that “the physical downlink control channel instructing to startthe random access procedure instructs the start of random accessprocedure with respect to the random access resource corresponding towhich downlink carrier component.” Therefore, the mobile stationapparatus can determine that “a physical downlink control channelinstructing to start the random access procedure, the physical downlinkcontrol channel being received by means of any one downlink carriercomponent among a plurality of downlink carrier components allocatedfrom the base station apparatus, is currently instructing to startrandom access procedure with respect to a random access resourcecorresponding to a preliminarily allocated specific downlink carriercomponent.” Moreover, the base station apparatus, based on the channelquality of a plurality of downlink carrier components allocated to themobile station apparatus, the overhead of a physical downlink controlchannel, or the like, can flexibly select a downlink carrier componentin which a physical downlink control channel instructing to start therandom access procedure is arranged.

(N) The wireless communication system of the present invention is awireless communication method, wherein a base station apparatus and atleast one mobile station apparatus perform a random access procedureusing a plurality of carrier components each defined by a differentfrequency band, the method comprising the steps of: selecting, amongrandom access resources corresponding to the respective downlink carriercomponents set in the mobile station apparatus, a random access resourcecausing the mobile station apparatus to start a random accesscommunication; and transmitting control information instructing to startrandom access procedure by means of a downlink carrier componentcorresponding to the selected random access resource.

In this manner, a base station apparatus notifies the physical downlinkcontrol channel instructing to start the random access procedure to amobile station apparatus by using a downlink carrier component which arandom access resource corresponds to, the random access resource bymeans of which the relevant physical downlink control channel instructsto start random access procedure. Therefore, the mobile stationapparatus, depending on by means of which downlink carrier componentamong a plurality of downlink carrier components allocated from the basestation apparatus, the physical downlink control channel instructing tostart the random access procedure has been received, can determine that“the relevant physical downlink control channel is currently instructingto start random access procedure with respect to the random accessresource corresponding to which downlink carrier component.” Moreover,the base station apparatus, based on the channel quality of a pluralityof uplink carrier components allocated to the mobile station apparatus,the transmission conditions (random access load) of the physical randomaccess channel, and the like, can flexibly select the uplink carriercomponent instructing to start the random access procedure.

(O) The wireless communication system of the present invention is awireless communication method, wherein a base station apparatus and atleast one mobile station apparatus perform a random access procedureusing a plurality of carrier components each defined by a differentfrequency band, the method comprising the step of: upon receipt of thecontrol information instructing to start random access procedure bymeans of any one downlink carrier component, starting random accessprocedure by means of a random access resource corresponding to aspecific downlink carrier component preliminarily allocated to the basestation apparatus.

In this manner, the mobile station apparatus determines that “a physicaldownlink control channel instructing to start the random accessprocedure, which is received by means of any one downlink carriercomponent of a plurality of downlink carrier components allocated fromthe base station apparatus, is instruction to start random accessprocedure with respect to a random access resource corresponding to apreliminarily allocated specific downlink carrier component.” Therefore,the base station apparatus, based on the channel quality of a pluralityof downlink carrier components allocated to the mobile stationapparatus, the overhead of a physical downlink control channel, or thelike, can flexibly select a downlink carrier component in which aphysical downlink control channel instructing to start the random accessprocedure is arranged.

(P) The wireless communication system of the present invention is awireless communication method, wherein a base station apparatus and atleast one mobile station apparatus perform a random access procedureusing a plurality of carrier components each defined by a differentfrequency band, the method comprising the step of: upon receipt of thecontrol information instructing to start random access procedure bymeans of any one downlink carrier component, starting random accessprocedure by means of a random access resource corresponding to thedownlink carrier component, by means of which the control information isreceived.

In this manner, the mobile station apparatus, depending on by means ofwhich downlink carrier component among a plurality of downlink carriercomponents allocated from the base station apparatus, the physicaldownlink control channel instructing to start the random accessprocedure has been received, determines that “the relevant physicaldownlink control channel is currently instructing to start random accessprocedure with respect to the random access resource corresponding towhich downlink carrier component.” Therefore, the base stationapparatus, based on the channel quality of a plurality of uplink carriercomponents allocated to the mobile station apparatus, the transmissionconditions (random access load) of the physical random access channel,and the like, can flexibly select the uplink carrier componentinstructing to start the random access procedure.

A program operating in the base station apparatuses 3, 7 and the mobilestation apparatuses 1, 5 according to the present invention may be aprogram (program making a computer function) which controls a CPU(Central Processor) and the like so as to realize the functions of theabove-described embodiments according to the present invention. Then,the information handled by these devices is temporarily stored in an RAM(Random Access Memory) during processing of the information, and theinformation is subsequently stored in various ROMs, such as a Flash ROM(Read Only Memory), or an HDD (Hard Disk Drive), and is read, modified,or rewritten by the CPU, as required.

Note that, some of or all of the mobile station apparatuses 1, 5 and thebase station apparatuses 3, 7 in the above-described embodiments may berealized by a computer. In this case, some of or all of the mobilestation apparatuses 1, 5 and the base station apparatuses 3, 7 in theabove-described embodiments may be realized by storing a program forrealizing this control function onto a computer readable recordingmedium, and causing a computer system to read and execute the programstored on this recording medium. Note that, the term “computer system”here refers to a computer system incorporated into the mobile stationapparatuses 1, 5 or the base station apparatuses 3, 7, wherein thecomputer system includes an OS and hardware, such as peripheral devices.

Moreover, the term “computer readable recording medium” refers to aportable medium, such as a flexible disk, a magnetic optical disk, aROM, or a CD-ROM, or a storage device, such as a hard disk incorporatedinto a computer system. Furthermore, the “computer readable recordingmedium” may include those dynamically retaining a program for a shorttime, like communication lines when a program is transmitted via anetwork, such as the Internet, or via a communication line, such as atelephone line, or those retaining a program for a certain time, like avolatile memory inside a computer system then serving as a server or aclient. Moreover, the above-described program may be the one forrealizing some of the above-described functions, or further may be theone capable of realizing the above-described functions in combinationwith a program already stored on a computer system.

Some of or all of the mobile station apparatuses 1, 5 and the basestation apparatuses 3, 7 in the above-described embodiments may berealized as an LSI which is typically an integrated circuit. Eachfunctional block of the mobile station apparatuses 1, 5 and the basestation apparatuses 3, 7 may be individually integrated into a chip orsome of or all thereof may be integrated into a chip. Moreover, theintegration approach is not limited to an LSI, but the integration maybe realized by an application specific circuit or a general-purposeprocessor. Moreover, if an integration technology replacing the LSIwould have emerged due to an advancement in the semiconductortechnologies, an integrated circuit by means of this technique may beused.

As described above, one embodiment of the present invention has beendescribed in detail With reference to the accompanying drawings, but aspecific configuration is not limited to the above-described one, andvarious kinds of design changes and the like can be made withoutdeparting from the scope of the present invention.

REFERENCE SIGNS LIST

-   1, 1A-1C, 5: mobile station apparatus-   3, 7: base station apparatus-   101, 301: higher layer processor-   103: preamble detector-   105: synchronization timing measurement unit-   107: controller-   109: reception processor-   111: transmission processor-   201, 401: higher layer processor-   203: controller-   205: reception processor-   207: preamble generator-   209: transmission processor-   1011, 3011: radio resource controller-   1012, 3012: random access controller-   2011: radio resource controller-   2012, 4012: random access processor

1. A base station apparatus, the base station apparatus configured tocommunicate with a mobile station apparatus using a plurality ofcomponent carriers, the base station apparatus comprising: atransmission unit configured to transmit to the mobile stationapparatus: a first control information indicative of a first set ofphysical random access channel resources on a first uplink componentcarrier, the first set of physical random access channel resourcescorresponding to a specific downlink component carrier, and a secondcontrol information indicative of a second set of physical random accesschannel resources on a second uplink component carrier, the second setof physical random access channel resources corresponding to a seconddownlink component carrier, and a third control information includinginformation instructing to start a random access procedure correspondingto one of the specific downlink component carrier and the seconddownlink component carrier and information indicative of a preamble; anda reception unit configured to receive a preamble, which the mobilestation apparatus randomly selected among determined group of preamblesto be selected in a case of all the pieces of the information indicativeof a preamble being set to zero, and which the mobile station apparatustransmitted using one physical random access channel resource that isselected from among one of the first and second sets of the physicalrandom access channel resources, one of the first and second sets of thephysical random access channel resources being determined based on thethird control information. the transmission unit configured to transmitto the mobile station apparatus: a random access response correspondingto the received preamble and including an uplink grant used for anallocation of a physical uplink shared channel resource on the one ofthe first and second uplink component carriers on which the preamble isreceived.
 2. The base station apparatus according to claim 1, whereinthe transmission unit is configured to transmit the random accessresponse using a specific downlink component carrier.
 3. The basestation apparatus according to claim 1, wherein the transmission unit isconfigured to transmit the random access response using the downlinkcomponent carrier corresponding to the uplink component carrier on whichthe preamble is transmitted.
 4. A mobile station apparatus, the mobilestation apparatus configured to communicate with a base stationapparatus using a plurality of component carriers, the mobile stationapparatus comprising: a setting unit configured to set first and secondsets of physical random access channel resources in accordance with thefirst and second control information received from the base stationapparatus, the first control information indicating the first set ofphysical random access channel resources corresponding to a specificdownlink component carrier, the second control information indicatingthe second set of physical random access channel resources correspondingto a second downlink component carrier; a determination unit configuredto determine a group of preamble to be selected; a selecting unitconfigured to: select, upon receipt of third control informationincluding information instructing to start a random access procedurecorresponding to one of the specific downlink component carrier and thesecond downlink component carrier and information indicative of apreamble from the base station apparatus, one physical random accesschannel resource from among one of the first and second sets of physicalrandom access channel resources, the one of the first and second sets ofthe physical random access channel resources being determined based onthe third control information, and randomly select one preamble fromamong the determined group of preambles in a case of all the pieces ofthe information indicative of a preamble being set to zero; atransmission unit configured to transmit the selected preamble using theselected physical random access channel resource; and a reception unitconfigured to receive, a random access response corresponding to thetransmitted preamble and including an uplink grant used for anallocation of a physical uplink shared channel resource on the one ofthe first and second uplink component carriers on which the selectedpreamble is transmitted.
 5. The mobile station apparatus according toclaim 4, wherein the reception unit is configured to receive the randomaccess response using a specific downlink component carrier.
 6. Themobile station apparatus according to claim 4, wherein the receptionunit is configured to receive the random access response using thedownlink component carrier corresponding to the uplink component carrieron which the preamble is transmitted.
 7. A wireless communication methodwhich is used in a base station apparatus that communicates with amobile station apparatus using a plurality of component carriers, thewireless communication method comprising: transmitting, to the mobilestation apparatus, a first control information indicative of a first setof physical random access channel resources on a first uplink componentcarrier, the first set of physical random access channel resourcescorresponding to a specific downlink component carrier, andtransmitting, to the mobile station apparatus, a second controlinformation indicative of a second set of physical random access channelresources on a second uplink component carrier, the second set ofphysical random access channel resources corresponding to a seconddownlink component carrier; transmitting, to the mobile stationapparatus, a third control information including information instructingto start a random access procedure corresponding to one of the specificdownlink component carrier and the second downlink component carrier andinformation indicative of a preamble; and receiving a preamble, whichthe mobile station apparatus randomly selected among determined group ofpreambles to be selected in a case of all the pieces of the informationindicative of a preamble being set to zero, and which the mobile stationapparatus transmitted using one physical random access channel resourcethat is selected from among one of the first and second sets of thephysical random access channel resources, the one of the first andsecond sets of the physical random access channel resources beingdetermined based on the third control information. transmitting, to themobile station apparatus, a random access response corresponding to thereceived preamble and including an uplink grant used for an allocationof a physical uplink shared channel resource on the one of the first andsecond uplink component carriers on which the preamble is received. 8.The wireless communication method which is used in a base stationapparatus according to claim 7, wherein transmitting, to the mobilestation apparatus, the random access response using a specific downlinkcomponent carrier.
 9. The wireless communication method which is used ina base station apparatus according to claim 7, wherein transmitting, tothe mobile station apparatus, the random access response using thedownlink component carrier corresponding to the uplink component carrieron which the preamble is transmitted.
 10. A wireless communicationmethod which is used in a mobile station apparatus that communicateswith a base station apparatus using a plurality of component carriers,the wireless communication method comprising: setting a first and secondsets of physical random access channel resources in accordance with thefirst and second control information received from the base stationapparatus, the first control information indicating the set of physicalrandom access channel resources corresponding to a specific downlinkcomponent carrier, the second control information indicating the set ofphysical random access channel resources corresponding to a seconddownlink component carrier; determining a group of preambles to beselected; selecting, upon receipt of a third control informationincluding information instructing to start a random access procedurecorresponding to one of the specific downlink component carrier and thesecond downlink component carrier and information indicative of apreamble from the base station apparatus, one physical random accesschannel resource form among one of the first and second sets of physicalrandom access channel resources in accordance with the second controlinformation, the one of the first and second sets of the physical randomaccess channel resources being determined based on the third controlinformation; randomly selecting one preamble from among the determinedgroup of preambles in a case of all the pieces of the informationindicative of a preamble being set to zero; transmitting the selectedpreamble using the selected physical random access channel resource; andreceiving, a random access response corresponding to the transmittedpreamble and including an uplink grant used for an allocation of aphysical uplink shared channel resource on the one of the first andsecond uplink component carriers on which the selected preamble istransmitted.
 11. The wireless communication method which is used in amobile station apparatus according to claim 10, wherein receiving therandom access response using a specific downlink component carrier. 12.The wireless communication method which is used in a mobile stationapparatus according to claim 10, wherein receiving the random accessresponse using the downlink component carrier corresponding to theuplink component carrier on which the preamble is transmitted.